Coherent oscillation in photocurrent through single-atom junctions at room temperature

Coherent oscillation in photocurrent through single-atom junctions at room temperature | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Coherent oscillation in photocurrent through single-atom junctions at room temperature Wenjing Hong, Lijue Chen, Jun-Rong Zheng, Hao Zhang, Zhixin Qiu, and 8 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6367654/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract Control of light-driven current at the nanoscale is essential for optoelectronics, energy transfer, and information processing, and the single-atom junctions preserving electron coherence serves as a model system with ultimate size to investigate and manipulate light-driven transport. However, the light-driven coherent transport through the single-atom junctions remains elusive due to the challenge of controlling their atomic topography at room temperature. Here, we demonstrate a photocurrent oscillation from photon-assisted coherent transport in single-atom junctions by controlling the atomic structure using the mechanically controllable break junction technique at ambient condition. Such an oscillation results in a giant suppression ratio of up to ~ 50% of the collective photocurrent, which disentangle the coherent interplay between two opposite transport pathways of photon-induced absorption and emission from the plasmon-induced hot-electron transport. Our findings offer an atomically precise strategy to control light-driven transport and open a new route toward atomic-scale high-frequency optoelectronics. Physical sciences/Nanoscience and technology/Nanoscale devices/Molecular electronics Physical sciences/Nanoscience and technology/Nanoscale devices/Nanophotonics and plasmonics Figures Figure 1 Figure 2 Figure 3 Figure 4 Main Light-driven current at the nanoscale has revolutionized the investigation of light-matter interaction and the development of quantum optoelectronic devices and ultrafast imaging techniques. 1 – 4 As the smallest conductor to accommodate the light-driven current, 5 – 8 single-atom point contacts offer the diversity of atomic structure to control the light-matter interactions. However, the light-driven coherent transport in single-atom junctions has not been demonstrated due to the challenge in the control of their atomic structure. 9 – 11 The mechanically controllable break junction (MCBJ) technique capable of manipulating atomic structures with even sub-picometer precision offers a unique tool to characterize the light-induced transport through the single-atom junctions. 12 – 14 The light-driven current through the quantum junctions in the model of two-dimensional electron gas was dominated by photon-assisted coherent transport showing photoconductance oscillation. 15 , 16 In contrast, the major contribution of photoconductance in metal atomic junctions is suggested to be the plasmon-induced hot-electron transport, owing to induced localized electromagnetic field enhancement under the photo-illumination on the metallic nanostructures. 17 , 18 However, the role of photon-assisted transport dependent on the energy band structure of atomic junctions is ignored mainly due to the structural diversity hidden by the previous static direct current (d.c.) photoconductance measurements. Simultaneous characterization and extraction of the d.c. conductance related to atomic structure and the alternating current (a.c.) photocurrent related to light-driven transport is promising to reveal the role of photon-assisted transport. Here, we demonstrate the coherent oscillation in the photocurrent through single-atom junctions by using the MCBJ technique with nano-lithographic sample chips. The oscillation results in a significant suppression of collective photocurrent with the formation of single-atom junctions during gold electrodes opening, and disappears when the formation is not observed during electrode closing. The control experiments further demonstrated that the suppressed photocurrent is irrelevant to the plasmon-induced photocurrent. Our theoretical model suggests that the competition between the emission and absorption pathways of photon-assisted transport accounts for the photocurrent oscillation. Theoretical model of photocurrent oscillation As illustrated in Fig. 1 a, the narrow constriction of nanojunctions (such as the single-atom junctions, which are also called atomic quantum junctions) determines the potential barrier for electrons transporting from source to drain. It only allows electrons in certain quantized states to transmit, which depends on the total energy of electron ε n and the eigenenergy of state at the narrowest part E n (Further discussion is presented in Note S1 ). With the variation of nano-constriction width, the eigenenergy E n changes synchronously, when it meets Fermi energy E F , a new transmitted or reflected state appears and contributes to d.c. conductance. Under the perturbation of an external electromagnetic field, electrons can transit to either an upper state with the eigenenergy of ε n+1 or a lower state with the eigenenergy of ε n−1 , via absorbing or emitting a photon with the energy of ħω respectively, as illustrated in Fig. 1 b, c. 7 Focusing on the absorption case of an electron with energy ε near Fermi level occupied at n state (denoted as ε n , Fig. 1 b), when the initial energy ε n > E n and final energy ε n+1 = ( ε n + ħω ) < E n+1 (0), the initial states are transmitted and final states are reflected. The transition from transmitted states to reflected states results in the depletion of transmitted states corresponding to the negative photoconductance. Another case that the transition between transmitted states does not influence the conductance is shown in the right panel of Fig. 1 b. For the cases of emission shown in Fig. 1 c, the transition from reflected states to transmitted states leads to the positive photoconductance due to the increase of population in transmitted states. As a consequence, the alternation between absorption and emission processes contributes to reverse photoconductance, thus brings the oscillation in photoconductance as presented in Fig. 1 d,e (Details of calculations are presented in Note S1 ). Such a phenomenon was reported in the quantum junctions formed in a two-dimensional electron gas system with the order of millielectron volts energy spacing via electrostatic gating, however, can not survive at room temperature due to the thermal fluctuation. 15 , 19 – 21 In contrast, the energy spacing of single-atom junctions in the order of electron volts allows the occurrence of oscillation at room temperature. 22 , 23 At elevated temperatures, the abrupt oscillations became much smoother due to the electron-phonon scattering mediated mixture of quantum modes (Detailed discussions are shown in Fig. S2 ). 24 Experimental observation of photocurrent oscillation As illustrated in Fig. 2 a, three geometric types of gold nano-constriction can form during the electrode stretching, corresponding to different electronic structures. The bulk of gold is a continuous band structure, and after the formation of gold atomic junctions, discrete energy levels dominate the transport. A smaller width of nano-constriction leads to larger energy spacing and lower conductance. Due to the flexibility of atomic junctions and single-atom junctions, the quantum conductance plateau appears during the stretch. After the breakdown of single-atom junctions, a nanogap forms then the electron tunneling dominates the transport behavior. To observe the photocurrent oscillation in atomic junctions, we introduce the multi-frequency demodulation strategy ( ω DC , ω PC , ω Ref ) into our MCBJ setup excited by a femtosecond laser as depicted in Fig. 2 a. A key advance of our method is that we build a direct correlation between atomic structure and photocurrent by simultaneously monitoring the d.c. current and a.c. photocurrent. 25 The I DC (d.c. current) is used to monitor the conductance change of a suspended gold nanowire during the break junction process (electrode opening and closing), and the I PC synchronized with an optical chopper is used to record the photocurrent. The shot noise measurements are usually conducted at a static status of single-atom junctions and reported to be suppressed. 26 , 27 Beyond the prevalent shot noise at high frequencies, it is imperative to account for the impact of mechanical and thermal noise at lower frequencies which collectively contribute to the flicker noise. It becomes particularly relevant when the frequency of this noise aligns with the detection frequency of the photocurrent. The linear bias-dependence of reference current ( Fig. S3 ) indicates the dominance of flicker noise rather than thermal noise. 27 In addition, the differential photocurrent allows us to eliminate the contribution of thermal noise due to its frequency independence. Therefore, we use a fully dynamical break junction method to probe and subtract the flicker noise from the photocurrent signal, which facilitates a more accurate characterization of the light-driven transport. As the typical trace during break junction process presented in Fig. 2 b, the quantized conductance plateau forms during the stretching (the Open process) of gold single-atom junction, which indicates the formation of gold atomic junctions. The smooth conductance curve is caused by the bandpass filter of a lock-in amplifier. Interestingly, a pronounced photocurrent oscillation at integer conductance plateaus is observed (lower panel of Fig. 2 b), which is consistent with the theoretical predictions in Fig. 1 d, demonstrating the competition of emission and absorption pathways in gold nanojunctions. The calculated results are calibrated by factors of power density and plasmonic enhancement factor. The discrepancy between line shape of theoretical curve and experimental curve is because the experimental photocurrent is mainly contributed by three different mechanisms, which are photon-assisted transport, plasmon-induced hot-electron transport and plasmonic field enhancement. 28 From the simulation of electron density and field enhancement factor presented in Fig. S4 , the plasmonic enhancement effects are increased before breaking down of nanojunction, which is consistent with the photocurrent before formation of a single-atom junction. To reveal the most probable distribution of single-atom junctions, we repeated the open-close process hundreds of times to histogram the photocurrent and conduction correlation. The conductance peak appears at 1 G 0 (conductance quantum which equals to 77.5 µS) in the one-dimensional conductance histograms shown in Fig. 2 c, indicating that the formation probability and lifetime of single-atom junctions during the Open process (representing the stretching of gold nanojunction) are significantly higher than that of the Close process (representing the electrodes pair joining together for further stretching). The jump-to-contact phenomena in Close process is not favorable for fabricating single-atom junction, thus leading to a smooth conductance transition around 1 G 0 . 29 , 30 The two-dimensional conductance histogram in Fig. S5 shows that the mechanical stability of gold nanowires in Close process is incompatible with that in Open processes, which lowers the stability and formation probability of single-atom junctions. For quantitative analysis of photocurrent oscillation, the Open photocurrent trace ( I Open ) and Close photocurrent trace ( I Close ) are obtained by averaging the data points with a certain conductance range shown in Fig. 2 d. 30 A sharp decrease in I Open is found around 1 G 0 , and the same feature appears in the flicker noise of the Open process. This feature disappears in both photocurrent and flicker noise of the Close process without the formation of single-atom junctions, suggesting the suppression is only observable in single-atom contact. 31 The simultaneously recorded I Ref around 1 G 0 is suppressed as well. The amplitude of I Ref is much weaker than I PC , demonstrating that the suppression of photocurrent is not caused by the change of flicker noise, which is supported by their value difference I Diff shown in Fig. S6 . The I Diff without irradiation around 0 nA suggests that the I Diff can serve as the net photocurrent, which is supported by the comparison of I Diff with and without irradiation. In addition, the formation probability and lifetime of single-atom junctions are sensitive to the electrode stretching rate during the open-close process. By tuning the stretching rate, we find that the photocurrent suppression disappears when the stretching rate is too high to form a stable single-atom junction ( Fig. S7 ). 32 The observation of collective photocurrent suppression in integer conductance quantum suggests that the suppression occurs whenever quantum junction forms ( Fig. S8) . Furthermore, no secondary dip in Fig. 2 d is detected in the tunneling region of the photocurrent and reference signals, supporting the negligible impact of contaminants on photocurrent measurement. Limited by the sampling method of our linear preamplifier and lock-in amplifier, the conductance regime is cut to -1.5 log( G / G 0 ) to 0.5 log( G / G 0 ). The signal becomes noisier near − 1 log( G / G 0 ) because the signal is close to the current background. A conductance histogram in conductance range between − 3.5 to -1.5 log( G / G 0 ) is presented in Fig. S9 , supporting the cleanliness of our MCBJ chip. More cases can be found in our previous reports. 33 – 35 Additionally, the photocurrent shows independence on mechanically stretching rate, suggesting the photocurrent is not modulated by the mechanical noise ( Fig. S10 ). 36 To clarify the negligible role of thermal effects in our results, we simulate the temperature change caused by femtosecond laser is merely ~ 0.1 mK ( Fig. S4b,c ) which is obviously ignorable. Even considering such a temperature change as a source of photothermoelectricity, only a thermal current of ~ 0.33 f A (estimated using Seebeck coefficient of ~ 4 µV/K for a single-gold atom point contact 37 ) is expected which is far lower than our results. Beside, the anisotropic distribution of photocurrent in spatial ( Fig. S11 ) rules out the dominance of photothermoelectricity because the photothermal current is expected to produce an anisotropic thermal current in nanogap. 38 Further, the power independence of anti-Stokes/Stokes signal ratio of the gold junction ( Fig. S12 ) suggests the temperature change by femtosecond laser is ignorable in our case. 39 The real-time measurement of our MCBJ method 33 , 34 enables sub-picometer scale modulation of electrode separation and also avoids the interruption of heat-induced variation of atomic contacts under laser irradiation because the conductance of junctions corresponding to the size of the atomic contacts is correlated with the photocurrent. Even though plasmonic heating can lead to the breakdown of atomic junctions, the resulting drop in conductance can be excluded through conductance-photocurrent correlation. 40 Such a synchronous multi-frequency measurement enables us to build a correlation of the photocurrent, flicker noise, and d.c. current in real-time with statistical analyses by repeating the open-close process. Plasmon-induced photocurrent To gain further quantitative insight, we presume that I Close represents the photocurrent from the non-suppressed state and I Open represents the suppressed states. Thus, we can quantify the influence of photon-assisted transport by the suppressed photocurrent ( I Open ─ I Close ). Fig. S13 presents the net photocurrent at excitation power of 1 mW and 6 mW, respectively, in which both I Open and I Close show a monotonic increase with power. As illustrated in Fig. 3 a, the suppressed photocurrent is proportional to the excitation power, and it follows a linear relationship with the power, suggesting the plasmon-induced transport dominates the intensity of photocurrent ( Fig. S13c ). 7 Further, the suppression ratio of photocurrent by using I Open / I Close ─1 can be evaluated as presented in Fig. 3 a. The independence of suppression ratio on excitation power suggests that the photocurrent is dominated by the plasmon-induced transport and the suppressed ratio represents the contribution of photon-assisted transport. 28 Moreover, the power-law exponents during the Open and Close processes shown in Fig. 3 b are almost identical with a value of ~ 1.1, suggesting that the one-photon-assisted transport dominates the photocurrent generation, 41 which confirms the applicability of one photon approximation in the transport model as illustrated in Fig. 1 b. In contrast to the near vanishment of shot noise at low temperatures, we speculate that the suppression ratio is limited by thermal fluctuation. Considering the plasmonic resonance is correlated to the nanostructure of metal while the photon-assisted transport is dominated by the narrowest part mediating transport, 42 , 43 their wavelength dependence displays the interaction and relationship between them. The collective suppression of photocurrent indicates the cancellation of photon-assisted transport while the plasmon-induced transport mainly contributes to the net photocurrent as illustrated in Fig. 4 a. Therefore, the photocurrent should be dominated by the plasmonic resonance and exhibit contrast behavior to the suppression ratio. As presented in Fig. 4 b, the photocurrent of single-atom junctions shows a double peak feature which is consistent with the calculated wavelength-dependence of optical absorption, suggesting that the absolute intensity change of photocurrent is dominated by the plasmon-enhancement effects of gold nanostructure as similar to previous findings. 28 The existence of dip features at 1 G 0 in Open photocurrent traces ( Fig. S14 ) showcases that the current of photon-assisted transport in single-atom junctions is suppressed within the excitation wavelength ranging from 700 to 900 nm. In addition, the suppression ratio (Fig. 4 c) as the indicator for photon-assisted transport shows an opposite tendency to photocurrent, suggesting that the current of photon-assisted transport is incoherent with the current by plasmon-induced transport. 28 Such a dependence of photon-assisted transport is a consequence of shifting the excitation energy window away for the electron modes of single-atom junctions, suggesting the transition of reflected states to transmitted states. 44 Meanwhile, the suppression presented in Fig. S15 shows bias independence within a proper range (below 200 mV for our sample). The high bias voltage can reduce the formation probabilities and lifetime of single-atom junctions, resulting in a reversed photocurrent trend for Open and Close processes. Conclusion In this work, we observed the significant coherent oscillation induced photocurrent suppression in the single-atom junctions at room temperature, allowing the precise control of the coherent competition via atomic structure, while the coherent competition between absorption and emission pathways in the framework of photon-assisted transport reported in two-dimensional electron gas system is only capable to survive at the temperature of milliKelvin 20 . The oscillation results in a giant suppression of up to ~ 50% photocurrent through single-atom junctions at room temperature, and the photon-assisted transport pathways are demonstrated to be not associated with the plasmon-induced transport pathway that we can separately modulate two mechanisms via controlling atomic structure. Our work demonstrates the capability of a.c. photocurrent measurement to extract structural information hidden by previous d.c. photoconductance measurement, which offers opportunities to investigate the real-time information of light-matter interactions at the scale of single-atom and future for single-molecule. 45 , 46 The capability of suppressing photon-assisted transport via atomic control opens a new route to functionalize room-temperature quantum devices and quantum plasmonic devices. 47 , 48 Methods MCBJ experiments and photocurrent measurement of single-atomic junctions. The setup and beam path are depicted in Fig. S16 . The details of the microfabrication of MCBJ chips can be found in our previous work. 33 , 34 The break junction processes are controlled by pushing and pulling the pod underneath the MCBJ chip driven by a motor. The two-terminal of MCBJ chip is connected to the current input and voltage output ports of lock-in amplifier (MFLI, Zurich Instruments) which consists of a linear pre-amplifier and a lock-in loop. The 0 Hz current from the lock-in amplifier serves as the feedback signal for break junctions. The femtosecond laser (Chameleon Ultra Ⅱ, Coherent Inc) is chopped for a frequency of 983 Hz and sent to MCBJ chip in free space. The photocurrent at 983 Hz and flicker noise at 1023 Hz are recorded in real time. The femtosecond laser is tunable in the range of 680 to 1080 nm with a repetition frequency of 80 MHz. The diameter of laser beam used in measurement is approximately 100 µm. Consequently, the power density for measurement is approximately 7.36 W/cm 2 (corresponding to peak power density of 2.3×10 6 W/cm 2 ) for per mW excitation. Photoconductance calculation The photoconductance of quantum point contacts is calculated through the transport model described in the main text for Fig. 1 . The detailed analytical derivation and formulation of the model are discussed in the supplementary information. In the linear regime where only one photon is absorbed or emitted, the overall photoconductance can be written as: Electromagnetic simulation The absorption spectrum of the nanoelectrodes pair in the nano-lithographic MCBJ chip is obtained by the commercial software COMSOL Multiphysics based on the finite element method. The geometry of MCBJ chip was inferred from SEM images ( Fig. S16b ), We only integrate the absorption throughout the center junction part of MCBJ to reflect the absorption of the atomic junction. Declarations Competing interests The authors declare no competing interests. Author contributions W. H. supervised the project. W. H., L. C. and J. L. originally conceived the concept and designed the experiments. H. Z., L. C. and J. S. designed and constructed the setup with the support of H. L. Z. Q., Y. J., J. Z. and J. L. prepared the MCBJ chips. L. C., H. Z. and Z. Q. performed the photocurrent measurements. H. Z. and Y. C. performed photoluminescence measurements. L. C. developed the data analysis method and analyzed the results. J. Y., J.-R. Z. carried out the calculations. L. C. prepared the manuscript with input from other authors. Acknowledgments This work was supported by the National Key Research and Development Program of China (2024YFA1208103), the Natural Science Foundation of China (22325303, 22173075, 22272140, 21933012), the Fujian Provincial Department of Science and Technology (2023H6002). We also acknowledge the support from the ultra-precision lab in IKKEM for offering the experimental platforms. Data availability All data that support the findings of this study are available from the corresponding author upon reasonable request. References Baumberg JJ, Aizpurua J, Mikkelsen MH (2019) Smith D. R. Extreme nanophotonics from ultrathin metallic gaps. 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Nat Rev Phys 3:441 Borsch M, Meierhofer M, Huber R, Kira M (2023) Lightwave electronics in condensed matter. Nat Rev Mater 8:668 Additional Declarations There is NO Competing Interest. Supplementary Files APCSINP.docx APC_SI_NP Cite Share Download PDF Status: Under Review Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6367654","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":453750939,"identity":"ea1782c4-f358-489e-b292-b02d6bbea7a9","order_by":0,"name":"Wenjing Hong","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAr0lEQVRIiWNgGAWjYDACCRBRgcQmUssZkrUwtpGixeB287GHX+cdjjY4wHzwNg+DXR5hLXeOpRvLbkvL3XCALdmahyG5mKAWsxs5ZtKS22yAWnjMpHkYDiQ2EKdljgRQC/834rVIfmwA28JGnBb7G2lp0gzH0nJnHmYztpxjkExYi+SM5GOSP2oO5/Ydb354402FHWEtIMDMAyZBhAEx6oGA8QeRCkfBKBgFo2CEAgCvSDsYhrRj3QAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0000-0003-4080-6175","institution":"Xiamen University","correspondingAuthor":true,"prefix":"","firstName":"Wenjing","middleName":"","lastName":"Hong","suffix":""},{"id":453750940,"identity":"650dcd6e-948f-459d-bc1b-db11796a938c","order_by":1,"name":"Lijue Chen","email":"","orcid":"https://orcid.org/0000-0002-8872-2723","institution":"Xiamen University","correspondingAuthor":false,"prefix":"","firstName":"Lijue","middleName":"","lastName":"Chen","suffix":""},{"id":453750941,"identity":"8af8c356-8467-4a9b-b844-fcf3c51f7cce","order_by":2,"name":"Jun-Rong Zheng","email":"","orcid":"https://orcid.org/0000-0001-9131-8388","institution":"Xiamen University","correspondingAuthor":false,"prefix":"","firstName":"Jun-Rong","middleName":"","lastName":"Zheng","suffix":""},{"id":453750942,"identity":"79ab5e07-4490-41fd-9015-b86cfb3168dc","order_by":3,"name":"Hao Zhang","email":"","orcid":"","institution":"Xiamen University","correspondingAuthor":false,"prefix":"","firstName":"Hao","middleName":"","lastName":"Zhang","suffix":""},{"id":453750943,"identity":"05c501fe-941a-4317-a6c0-c15d995a81e5","order_by":4,"name":"Zhixin Qiu","email":"","orcid":"","institution":"Xiamen University","correspondingAuthor":false,"prefix":"","firstName":"Zhixin","middleName":"","lastName":"Qiu","suffix":""},{"id":453750944,"identity":"0225a0df-9317-4d28-821d-7d4b45f9c19c","order_by":5,"name":"Yiqiang Jiang","email":"","orcid":"","institution":"Xiamen University","correspondingAuthor":false,"prefix":"","firstName":"Yiqiang","middleName":"","lastName":"Jiang","suffix":""},{"id":453750945,"identity":"10a110f7-8d97-4c0a-8cf5-a9b7deec425e","order_by":6,"name":"Jueting Zheng","email":"","orcid":"https://orcid.org/0000-0001-8437-2677","institution":"Xiamen University","correspondingAuthor":false,"prefix":"","firstName":"Jueting","middleName":"","lastName":"Zheng","suffix":""},{"id":453750946,"identity":"13ba586d-a463-40bc-a96a-867b4041affe","order_by":7,"name":"Yu Cao","email":"","orcid":"","institution":"Xiamen University","correspondingAuthor":false,"prefix":"","firstName":"Yu","middleName":"","lastName":"Cao","suffix":""},{"id":453750947,"identity":"7bc7f567-3f3e-4377-a873-5cdcf9f423f7","order_by":8,"name":"Haojie Liu","email":"","orcid":"","institution":"Xiamen University","correspondingAuthor":false,"prefix":"","firstName":"Haojie","middleName":"","lastName":"Liu","suffix":""},{"id":453750948,"identity":"b190c1cf-5d9c-43a5-a088-c97cb6116e38","order_by":9,"name":"Jia Shi","email":"","orcid":"","institution":"State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, Xiamen University","correspondingAuthor":false,"prefix":"","firstName":"Jia","middleName":"","lastName":"Shi","suffix":""},{"id":453750949,"identity":"865d221b-d1a3-473d-a246-25c211e02136","order_by":10,"name":"Junyang Liu","email":"","orcid":"","institution":"Xiamen University","correspondingAuthor":false,"prefix":"","firstName":"Junyang","middleName":"","lastName":"Liu","suffix":""},{"id":453750950,"identity":"73e8b8f3-94da-46f6-bdef-7377bb8b19fd","order_by":11,"name":"Jun Yi","email":"","orcid":"https://orcid.org/0000-0003-2186-6615","institution":"School of Electronic Science and Engineering","correspondingAuthor":false,"prefix":"","firstName":"Jun","middleName":"","lastName":"Yi","suffix":""},{"id":453750951,"identity":"0566d53a-f3db-4397-8c69-f9e3cea2a54a","order_by":12,"name":"Zhong-Qun Tian","email":"","orcid":"https://orcid.org/0000-0002-9775-8189","institution":"State Key Laboratory of Physical Chemistry of Solid Surfaces,College of Chemistry and Chemical Engineering, IKKEM, Xiamen University","correspondingAuthor":false,"prefix":"","firstName":"Zhong-Qun","middleName":"","lastName":"Tian","suffix":""}],"badges":[],"createdAt":"2025-04-03 09:02:43","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6367654/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6367654/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":83823206,"identity":"21bc3928-6726-4e74-888a-d912725ca0ac","added_by":"auto","created_at":"2025-06-03 09:24:09","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":796225,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eScheme of coherent oscillation between absorption and emission pathways in single-atom junctions. a,\u003c/strong\u003e The real-space geometry of a nanojunction, the width of the junction at each position is \u003cem\u003eD\u003c/em\u003e(\u003cem\u003ex\u003c/em\u003e), the nano-constriction (narrowest part) of the junction is defined as the origin of x-axis and the width is defined as \u003cem\u003ed\u003c/em\u003e. The bottom panel is the energy-space schematics of energy diagrams of nanojunction.\u003cem\u003e E\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e(\u003cem\u003ex\u003c/em\u003e) indicates the eigenenergy of \u003cem\u003en\u003c/em\u003eth state of the nano-constriction. The grey area indicates the potential barrier for charge transport. \u003cstrong\u003eb\u003c/strong\u003e, Schematics of two possible absorption pathways. Left panel illustrates the transition from a transmitted state to a reflected state. Right panel illustrates the transition from a transmitted state to a transmitted state. \u003cstrong\u003ec\u003c/strong\u003e, Schematics of two possible emission pathways. Left panel illustrates the transition from a reflected state to a transmitted state. Right panel illustrates the transition from a transmitted state to a transmitted state. \u003cem\u003ee\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e indicates an electron with energy \u003cem\u003ee \u003c/em\u003eoccupied at \u003cem\u003en\u003c/em\u003e state. \u003cem\u003eE\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e(0) indicates the eigenenergy of \u003cem\u003en\u003c/em\u003eth state at x = 0 of nano-constriction. Black cross indicates reflected. Check mark indicates transmitted. \u003cstrong\u003ed\u003c/strong\u003e, Calculated conductance (blue) and photocurrent (red) as a function of the width of nano-constriction. The photocurrent is the sum of the photoconductance of absorption pathway and emission pathway multiplied by 0.1 V. \u003cem\u003ek\u003c/em\u003e\u003csub\u003eF \u003c/sub\u003eis the velocity of electrons. \u003cstrong\u003ee\u003c/strong\u003e, The enlarged view of photocurrent around 1 \u003cem\u003eG\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e (conductance quantum which equals to 77.5 mS) from \u003cstrong\u003ed\u003c/strong\u003e. The yellow and purple lines are the photocurrent that originates from the absorption and emission pathways. The shadow areas are guides to the eye.\u003c/p\u003e","description":"","filename":"image1.png","url":"https://assets-eu.researchsquare.com/files/rs-6367654/v1/375a93d96dbafb8cb26ce814.png"},{"id":83823203,"identity":"580df24e-b1b4-4c69-a48c-da35428f3f8e","added_by":"auto","created_at":"2025-06-03 09:24:09","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":348681,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eObservation of coherent oscillation in photocurrent through atomic junctions. a\u003c/strong\u003e,\u003cstrong\u003e \u003c/strong\u003eScheme of laser-combined MCBJ setup with multifrequency demodulation function. The femtosecond laser with a tunable wavelength range from 680 to 1080 nm, a pulse length of ~140 \u003cem\u003ef\u003c/em\u003es, and a repetition frequency of 80 MHz is modulated by an optical chopper to a frequency of \u003cem\u003ew\u003c/em\u003e\u003csub\u003ePC\u003c/sub\u003e = 983 Hz and focused onto the suspended gold nanowire centered at the MCBJ chip using an objective.\u003cstrong\u003e \u003c/strong\u003eA bias voltage (\u003cem\u003eV\u003c/em\u003e\u003csub\u003ebias\u003c/sub\u003e) of 100 mV is applied to the two terminals of the gold nanowire. The d.c. current (\u003cem\u003ew\u003c/em\u003e\u003csub\u003eDC\u003c/sub\u003e = 0 Hz), a.c. photocurrent (\u003cem\u003ew\u003c/em\u003e\u003csub\u003ePC\u003c/sub\u003e = 983 Hz), and a.c. flicker noise (\u003cem\u003ew\u003c/em\u003e\u003csub\u003eRef\u003c/sub\u003e = 1023 Hz) are demodulated and recorded simultaneously using the lock-in amplifier. The inset is the SEM image of the nano-lithographic MCBJ chip. The bottom panel shows the energy level and geometry evolution of nanojunction during the open-close process. The width of nano-constriction \u003cem\u003ed\u003c/em\u003e\u003csub\u003e1\u003c/sub\u003e is larger than \u003cem\u003ed\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e, resulting in a energy spacing \u003cem\u003eE\u003c/em\u003e(\u003cem\u003ed\u003c/em\u003e\u003csub\u003e1\u003c/sub\u003e) \u0026lt; \u003cem\u003eE\u003c/em\u003e(\u003cem\u003ed\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e). \u003cstrong\u003eb\u003c/strong\u003e, Typical trace of conductance \u003cem\u003eI\u003c/em\u003e\u003csub\u003eDC\u003c/sub\u003e\u003csub\u003e\u003cem\u003e \u003c/em\u003e\u003c/sub\u003e(blue), photocurrent \u003cem\u003eI\u003c/em\u003e\u003csub\u003ePC\u003c/sub\u003e (red) and reference current \u003cem\u003eI\u003c/em\u003e\u003csub\u003eRef\u003c/sub\u003e (grey) were recorded simultaneously when the conductance quantum forms. \u003cem\u003eN\u003c/em\u003e indicates the integer of atomic junctions. Yellow balls indicate the gold atoms. \u003cstrong\u003ec\u003c/strong\u003e, The one-dimensional d.c. conductance histogram of Open (blue) and Close (red) processes. \u003cstrong\u003ed\u003c/strong\u003e, The photocurrent \u003cem\u003eI\u003c/em\u003e\u003csub\u003ePC\u003c/sub\u003e (top panel) and flicker noise \u003cem\u003eI\u003c/em\u003e\u003csub\u003eRef\u003c/sub\u003e (bottom panel) as a function of conductance averaged from ~400 traces with a conductance step of 0.01 log(\u003cem\u003eG\u003c/em\u003e/\u003cem\u003eG\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e). The grey lines are the suppression ratio obtained by (\u003cem\u003eI\u003c/em\u003e\u003csub\u003eClose\u003c/sub\u003e/\u003cem\u003eI\u003c/em\u003e\u003csub\u003eOpen\u003c/sub\u003e─1). The excitation wavelength: 700 nm, excitation power: 4 mW, and the bias voltage between source and drain electrodes: 0.1 V.\u003c/p\u003e","description":"","filename":"image2.png","url":"https://assets-eu.researchsquare.com/files/rs-6367654/v1/37d5b3dd292a58c510d35cd2.png"},{"id":83823207,"identity":"b86cc60e-fa32-4577-971c-2688d43f9566","added_by":"auto","created_at":"2025-06-03 09:24:09","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":213723,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eRobust suppression of photon-assisted transport through single-atom junctions.\u003c/strong\u003e \u003cstrong\u003ea,\u003c/strong\u003e The suppressed photocurrent (\u003cem\u003eI\u003c/em\u003e\u003csub\u003eOpen\u003c/sub\u003e─\u003cem\u003eI\u003c/em\u003e\u003csub\u003eClose\u003c/sub\u003e) and suppression ratio (\u003cem\u003eI\u003c/em\u003e\u003csub\u003eOpen\u003c/sub\u003e/\u003cem\u003eI\u003c/em\u003e\u003csub\u003eClose\u003c/sub\u003e─1) at different excitation power from 1 mW to 6 mW.\u003csub\u003e \u003c/sub\u003eThe dashed lines indicate the position of single-atom junction. Dashed grey\u003csub\u003e \u003c/sub\u003eline represents 0 on the \u003cem\u003ex\u003c/em\u003e-axis. PAT indicates the photon-assisted transport. \u003cstrong\u003eb\u003c/strong\u003e, Conductance resolved power-law exponent of Open and Close processes. Inset shows the energy diagram of one-photon excitation in our experimental condition. The excitation wavelength: 700 nm, bias voltage: 0.1 V.\u003c/p\u003e","description":"","filename":"image3.png","url":"https://assets-eu.researchsquare.com/files/rs-6367654/v1/cf5ca536243134df02b3bd2f.png"},{"id":83823205,"identity":"b5dc8e04-7a83-4eaf-8fbf-2c804544ed9c","added_by":"auto","created_at":"2025-06-03 09:24:09","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":530709,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ePlasmonic enhancement in single-atom junctions. a, \u003c/strong\u003eThe energy diagram shows the difference between photon-assisted transport and plasmon-induced transport. The cross indicates the photon-assisted transport pathway is partially blocked? due to the coherent oscillation between absorption and emission pathways.\u003cstrong\u003e b\u003c/strong\u003e, Wavelength-dependence of photocurrent at 1 \u003cem\u003eG\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e and the simulated photocurrent.\u003cstrong\u003e c\u003c/strong\u003e, Suppression ratio under excitation of different wavelengths at 0.1, 1, 2 \u003cem\u003eG\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e. The grey area indicates the suppression area. The excitation power: 6 mW, bias voltage: 0.1 V.\u003c/p\u003e","description":"","filename":"image4.png","url":"https://assets-eu.researchsquare.com/files/rs-6367654/v1/4fc25206a1ec30130e2b2340.png"},{"id":83824380,"identity":"d7309bbf-fc0c-4041-90e6-e25823dcb83c","added_by":"auto","created_at":"2025-06-03 09:40:11","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2541559,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6367654/v1/bc3c2f9c-035b-47bc-85ab-b9e907bd8a12.pdf"},{"id":83823211,"identity":"3e0e52fc-48ae-4fef-b4b6-b5d15ed01af1","added_by":"auto","created_at":"2025-06-03 09:24:10","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":3775239,"visible":true,"origin":"","legend":"APC_SI_NP","description":"","filename":"APCSINP.docx","url":"https://assets-eu.researchsquare.com/files/rs-6367654/v1/5547717b4ed4b5d852c90304.docx"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"Coherent oscillation in photocurrent through single-atom junctions at room temperature","fulltext":[{"header":"Main","content":"\u003cp\u003eLight-driven current at the nanoscale has revolutionized the investigation of light-matter interaction and the development of quantum optoelectronic devices and ultrafast imaging techniques.\u003csup\u003e\u003cspan additionalcitationids=\"CR2 CR3\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e As the smallest conductor to accommodate the light-driven current,\u003csup\u003e\u003cspan additionalcitationids=\"CR6 CR7\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e single-atom point contacts offer the diversity of atomic structure to control the light-matter interactions. However, the light-driven coherent transport in single-atom junctions has not been demonstrated due to the challenge in the control of their atomic structure.\u003csup\u003e\u003cspan additionalcitationids=\"CR10\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e The mechanically controllable break junction (MCBJ) technique capable of manipulating atomic structures with even sub-picometer precision offers a unique tool to characterize the light-induced transport through the single-atom junctions.\u003csup\u003e\u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eThe light-driven current through the quantum junctions in the model of two-dimensional electron gas was dominated by photon-assisted coherent transport showing photoconductance oscillation.\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e In contrast, the major contribution of photoconductance in metal atomic junctions is suggested to be the plasmon-induced hot-electron transport, owing to induced localized electromagnetic field enhancement under the photo-illumination on the metallic nanostructures.\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e However, the role of photon-assisted transport dependent on the energy band structure of atomic junctions is ignored mainly due to the structural diversity hidden by the previous static direct current (d.c.) photoconductance measurements. Simultaneous characterization and extraction of the d.c. conductance related to atomic structure and the alternating current (a.c.) photocurrent related to light-driven transport is promising to reveal the role of photon-assisted transport.\u003c/p\u003e \u003cp\u003eHere, we demonstrate the coherent oscillation in the photocurrent through single-atom junctions by using the MCBJ technique with nano-lithographic sample chips. The oscillation results in a significant suppression of collective photocurrent with the formation of single-atom junctions during gold electrodes opening, and disappears when the formation is not observed during electrode closing. The control experiments further demonstrated that the suppressed photocurrent is irrelevant to the plasmon-induced photocurrent. Our theoretical model suggests that the competition between the emission and absorption pathways of photon-assisted transport accounts for the photocurrent oscillation.\u003c/p\u003e\n\u003ch3\u003eTheoretical model of photocurrent oscillation\u003c/h3\u003e\n\u003cp\u003eAs illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea, the narrow constriction of nanojunctions (such as the single-atom junctions, which are also called atomic quantum junctions) determines the potential barrier for electrons transporting from source to drain. It only allows electrons in certain quantized states to transmit, which depends on the total energy of electron \u003cem\u003eε\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e and the eigenenergy of state at the narrowest part \u003cem\u003eE\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e (Further discussion is presented in \u003cb\u003eNote S1\u003c/b\u003e). With the variation of nano-constriction width, the eigenenergy \u003cem\u003eE\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e changes synchronously, when it meets Fermi energy \u003cem\u003eE\u003c/em\u003e\u003csub\u003eF\u003c/sub\u003e, a new transmitted or reflected state appears and contributes to d.c. conductance. Under the perturbation of an external electromagnetic field, electrons can transit to either an upper state with the eigenenergy of \u003cem\u003eε\u003c/em\u003e\u003csub\u003en+1\u003c/sub\u003e or a lower state with the eigenenergy of \u003cem\u003eε\u003c/em\u003e\u003csub\u003en\u0026minus;1\u003c/sub\u003e, via absorbing or emitting a photon with the energy of \u003cem\u003eħω\u003c/em\u003e respectively, as illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb, c.\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e Focusing on the absorption case of an electron with energy \u003cem\u003eε \u003c/em\u003enear Fermi level occupied at \u003cem\u003en\u003c/em\u003e state (denoted as \u003cem\u003eε\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e, Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb), when the initial energy \u003cem\u003eε\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e\u0026thinsp;\u0026gt;\u0026thinsp;\u003cem\u003eE\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e and final energy \u003cem\u003eε\u003c/em\u003e\u003csub\u003en+1\u003c/sub\u003e = (\u003cem\u003eε\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e+\u003cem\u003eħω\u003c/em\u003e)\u0026thinsp;\u0026lt;\u0026thinsp;\u003cem\u003eE\u003c/em\u003e\u003csub\u003en+1\u003c/sub\u003e(0), the initial states are transmitted and final states are reflected. The transition from transmitted states to reflected states results in the depletion of transmitted states corresponding to the negative photoconductance. Another case that the transition between transmitted states does not influence the conductance is shown in the right panel of Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb. For the cases of emission shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ec, the transition from reflected states to transmitted states leads to the positive photoconductance due to the increase of population in transmitted states.\u003c/p\u003e \u003cp\u003eAs a consequence, the alternation between absorption and emission processes contributes to reverse photoconductance, thus brings the oscillation in photoconductance as presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ed,e (Details of calculations are presented in \u003cb\u003eNote S1\u003c/b\u003e). Such a phenomenon was reported in the quantum junctions formed in a two-dimensional electron gas system with the order of millielectron volts energy spacing via electrostatic gating, however, can not survive at room temperature due to the thermal fluctuation.\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan additionalcitationids=\"CR20\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e In contrast, the energy spacing of single-atom junctions in the order of electron volts allows the occurrence of oscillation at room temperature.\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e At elevated temperatures, the abrupt oscillations became much smoother due to the electron-phonon scattering mediated mixture of quantum modes (Detailed discussions are shown in \u003cb\u003eFig. S2\u003c/b\u003e).\u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eExperimental observation of photocurrent oscillation\u003c/h2\u003e \u003cp\u003eAs illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea, three geometric types of gold nano-constriction can form during the electrode stretching, corresponding to different electronic structures. The bulk of gold is a continuous band structure, and after the formation of gold atomic junctions, discrete energy levels dominate the transport. A smaller width of nano-constriction leads to larger energy spacing and lower conductance. Due to the flexibility of atomic junctions and single-atom junctions, the quantum conductance plateau appears during the stretch. After the breakdown of single-atom junctions, a nanogap forms then the electron tunneling dominates the transport behavior.\u003c/p\u003e \u003cp\u003eTo observe the photocurrent oscillation in atomic junctions, we introduce the multi-frequency demodulation strategy (\u003cem\u003eω\u003c/em\u003e\u003csub\u003eDC\u003c/sub\u003e, \u003cem\u003eω\u003c/em\u003e\u003csub\u003ePC\u003c/sub\u003e, \u003cem\u003eω\u003c/em\u003e\u003csub\u003eRef\u003c/sub\u003e) into our MCBJ setup excited by a femtosecond laser as depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea. A key advance of our method is that we build a direct correlation between atomic structure and photocurrent by simultaneously monitoring the d.c. current and a.c. photocurrent.\u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e The \u003cem\u003eI\u003c/em\u003e\u003csub\u003eDC\u003c/sub\u003e (d.c. current) is used to monitor the conductance change of a suspended gold nanowire during the break junction process (electrode opening and closing), and the \u003cem\u003eI\u003c/em\u003e\u003csub\u003ePC\u003c/sub\u003e synchronized with an optical chopper is used to record the photocurrent. The shot noise measurements are usually conducted at a static status of single-atom junctions and reported to be suppressed.\u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e Beyond the prevalent shot noise at high frequencies, it is imperative to account for the impact of mechanical and thermal noise at lower frequencies which collectively contribute to the flicker noise. It becomes particularly relevant when the frequency of this noise aligns with the detection frequency of the photocurrent. The linear bias-dependence of reference current (\u003cb\u003eFig. S3\u003c/b\u003e) indicates the dominance of flicker noise rather than thermal noise.\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e In addition, the differential photocurrent allows us to eliminate the contribution of thermal noise due to its frequency independence. Therefore, we use a fully dynamical break junction method to probe and subtract the flicker noise from the photocurrent signal, which facilitates a more accurate characterization of the light-driven transport.\u003c/p\u003e \u003cp\u003eAs the typical trace during break junction process presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb, the quantized conductance plateau forms during the stretching (the Open process) of gold single-atom junction, which indicates the formation of gold atomic junctions. The smooth conductance curve is caused by the bandpass filter of a lock-in amplifier. Interestingly, a pronounced photocurrent oscillation at integer conductance plateaus is observed (lower panel of Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb), which is consistent with the theoretical predictions in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ed, demonstrating the competition of emission and absorption pathways in gold nanojunctions. The calculated results are calibrated by factors of power density and plasmonic enhancement factor. The discrepancy between line shape of theoretical curve and experimental curve is because the experimental photocurrent is mainly contributed by three different mechanisms, which are photon-assisted transport, plasmon-induced hot-electron transport and plasmonic field enhancement.\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e From the simulation of electron density and field enhancement factor presented in \u003cb\u003eFig. S4\u003c/b\u003e, the plasmonic enhancement effects are increased before breaking down of nanojunction, which is consistent with the photocurrent before formation of a single-atom junction.\u003c/p\u003e \u003cp\u003eTo reveal the most probable distribution of single-atom junctions, we repeated the open-close process hundreds of times to histogram the photocurrent and conduction correlation. The conductance peak appears at 1 \u003cem\u003eG\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e (conductance quantum which equals to 77.5 \u0026micro;S) in the one-dimensional conductance histograms shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ec, indicating that the formation probability and lifetime of single-atom junctions during the Open process (representing the stretching of gold nanojunction) are significantly higher than that of the Close process (representing the electrodes pair joining together for further stretching). The jump-to-contact phenomena in Close process is not favorable for fabricating single-atom junction, thus leading to a smooth conductance transition around 1 \u003cem\u003eG\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e.\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e The two-dimensional conductance histogram in \u003cb\u003eFig. S5\u003c/b\u003e shows that the mechanical stability of gold nanowires in Close process is incompatible with that in Open processes, which lowers the stability and formation probability of single-atom junctions. For quantitative analysis of photocurrent oscillation, the Open photocurrent trace (\u003cem\u003eI\u003c/em\u003e\u003csub\u003eOpen\u003c/sub\u003e) and Close photocurrent trace (\u003cem\u003eI\u003c/em\u003e\u003csub\u003eClose\u003c/sub\u003e) are obtained by averaging the data points with a certain conductance range shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ed.\u003csup\u003e\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e A sharp decrease in \u003cem\u003eI\u003c/em\u003e\u003csub\u003eOpen\u003c/sub\u003e is found around 1 \u003cem\u003eG\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e, and the same feature appears in the flicker noise of the Open process. This feature disappears in both photocurrent and flicker noise of the Close process without the formation of single-atom junctions, suggesting the suppression is only observable in single-atom contact.\u003csup\u003e\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003e The simultaneously recorded \u003cem\u003eI\u003c/em\u003e\u003csub\u003eRef\u003c/sub\u003e around 1 \u003cem\u003eG\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e is suppressed as well. The amplitude of \u003cem\u003eI\u003c/em\u003e\u003csub\u003eRef\u003c/sub\u003e is much weaker than \u003cem\u003eI\u003c/em\u003e\u003csub\u003ePC\u003c/sub\u003e, demonstrating that the suppression of photocurrent is not caused by the change of flicker noise, which is supported by their value difference \u003cem\u003eI\u003c/em\u003e\u003csub\u003eDiff\u003c/sub\u003e shown in \u003cb\u003eFig. S6\u003c/b\u003e. The \u003cem\u003eI\u003c/em\u003e\u003csub\u003eDiff\u003c/sub\u003e without irradiation around 0 nA suggests that the \u003cem\u003eI\u003c/em\u003e\u003csub\u003eDiff\u003c/sub\u003e can serve as the net photocurrent, which is supported by the comparison of \u003cem\u003eI\u003c/em\u003e\u003csub\u003eDiff\u003c/sub\u003e with and without irradiation. In addition, the formation probability and lifetime of single-atom junctions are sensitive to the electrode stretching rate during the open-close process. By tuning the stretching rate, we find that the photocurrent suppression disappears when the stretching rate is too high to form a stable single-atom junction (\u003cb\u003eFig. S7\u003c/b\u003e).\u003csup\u003e\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e The observation of collective photocurrent suppression in integer conductance quantum suggests that the suppression occurs whenever quantum junction forms (\u003cb\u003eFig. S8)\u003c/b\u003e.\u003c/p\u003e \u003cp\u003eFurthermore, no secondary dip in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ed is detected in the tunneling region of the photocurrent and reference signals, supporting the negligible impact of contaminants on photocurrent measurement. Limited by the sampling method of our linear preamplifier and lock-in amplifier, the conductance regime is cut to -1.5 log(\u003cem\u003eG\u003c/em\u003e/\u003cem\u003eG\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e) to 0.5 log(\u003cem\u003eG\u003c/em\u003e/\u003cem\u003eG\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e). The signal becomes noisier near \u0026minus;\u0026thinsp;1 log(\u003cem\u003eG\u003c/em\u003e/\u003cem\u003eG\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e) because the signal is close to the current background. A conductance histogram in conductance range between \u0026minus;\u0026thinsp;3.5 to -1.5 log(\u003cem\u003eG\u003c/em\u003e/\u003cem\u003eG\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e) is presented in \u003cb\u003eFig. S9\u003c/b\u003e, supporting the cleanliness of our MCBJ chip. More cases can be found in our previous reports.\u003csup\u003e\u003cspan additionalcitationids=\"CR34\" citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e Additionally, the photocurrent shows independence on mechanically stretching rate, suggesting the photocurrent is not modulated by the mechanical noise (\u003cb\u003eFig. S10\u003c/b\u003e).\u003csup\u003e\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eTo clarify the negligible role of thermal effects in our results, we simulate the temperature change caused by femtosecond laser is merely\u0026thinsp;~\u0026thinsp;0.1 mK (\u003cb\u003eFig. S4b,c\u003c/b\u003e) which is obviously ignorable. Even considering such a temperature change as a source of photothermoelectricity, only a thermal current of ~\u0026thinsp;0.33 \u003cem\u003ef\u003c/em\u003eA (estimated using Seebeck coefficient of ~\u0026thinsp;4 \u0026micro;V/K for a single-gold atom point contact\u003csup\u003e\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e\u003c/sup\u003e) is expected which is far lower than our results. Beside, the anisotropic distribution of photocurrent in spatial (\u003cb\u003eFig. S11\u003c/b\u003e) rules out the dominance of photothermoelectricity because the photothermal current is expected to produce an anisotropic thermal current in nanogap.\u003csup\u003e\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e\u003c/sup\u003e Further, the power independence of anti-Stokes/Stokes signal ratio of the gold junction (\u003cb\u003eFig. S12\u003c/b\u003e) suggests the temperature change by femtosecond laser is ignorable in our case.\u003csup\u003e\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eThe real-time measurement of our MCBJ method\u003csup\u003e\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e enables sub-picometer scale modulation of electrode separation and also avoids the interruption of heat-induced variation of atomic contacts under laser irradiation because the conductance of junctions corresponding to the size of the atomic contacts is correlated with the photocurrent. Even though plasmonic heating can lead to the breakdown of atomic junctions, the resulting drop in conductance can be excluded through conductance-photocurrent correlation.\u003csup\u003e\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e\u003c/sup\u003e Such a synchronous multi-frequency measurement enables us to build a correlation of the photocurrent, flicker noise, and d.c. current in real-time with statistical analyses by repeating the open-close process.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003ePlasmon-induced photocurrent\u003c/h3\u003e\n\u003cp\u003eTo gain further quantitative insight, we presume that \u003cem\u003eI\u003c/em\u003e\u003csub\u003eClose\u003c/sub\u003e represents the photocurrent from the non-suppressed state and \u003cem\u003eI\u003c/em\u003e\u003csub\u003eOpen\u003c/sub\u003e represents the suppressed states. Thus, we can quantify the influence of photon-assisted transport by the suppressed photocurrent (\u003cem\u003eI\u003c/em\u003e\u003csub\u003eOpen\u003c/sub\u003e─\u003cem\u003eI\u003c/em\u003e\u003csub\u003eClose\u003c/sub\u003e). \u003cb\u003eFig. S13\u003c/b\u003e presents the net photocurrent at excitation power of 1 mW and 6 mW, respectively, in which both \u003cem\u003eI\u003c/em\u003e\u003csub\u003eOpen\u003c/sub\u003e and \u003cem\u003eI\u003c/em\u003e\u003csub\u003eClose\u003c/sub\u003e show a monotonic increase with power. As illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea, the suppressed photocurrent is proportional to the excitation power, and it follows a linear relationship with the power, suggesting the plasmon-induced transport dominates the intensity of photocurrent (\u003cb\u003eFig. S13c\u003c/b\u003e).\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e Further, the suppression ratio of photocurrent by using \u003cem\u003eI\u003c/em\u003e\u003csub\u003eOpen\u003c/sub\u003e/\u003cem\u003eI\u003c/em\u003e\u003csub\u003eClose\u003c/sub\u003e─1 can be evaluated as presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea. The independence of suppression ratio on excitation power suggests that the photocurrent is dominated by the plasmon-induced transport and the suppressed ratio represents the contribution of photon-assisted transport.\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e Moreover, the power-law exponents during the Open and Close processes shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb are almost identical with a value of ~\u0026thinsp;1.1, suggesting that the one-photon-assisted transport dominates the photocurrent generation,\u003csup\u003e\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e\u003c/sup\u003e which confirms the applicability of one photon approximation in the transport model as illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb. In contrast to the near vanishment of shot noise at low temperatures, we speculate that the suppression ratio is limited by thermal fluctuation.\u003c/p\u003e \u003cp\u003eConsidering the plasmonic resonance is correlated to the nanostructure of metal while the photon-assisted transport is dominated by the narrowest part mediating transport,\u003csup\u003e\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e, \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e\u003c/sup\u003e their wavelength dependence displays the interaction and relationship between them. The collective suppression of photocurrent indicates the cancellation of photon-assisted transport while the plasmon-induced transport mainly contributes to the net photocurrent as illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ea. Therefore, the photocurrent should be dominated by the plasmonic resonance and exhibit contrast behavior to the suppression ratio. As presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eb, the photocurrent of single-atom junctions shows a double peak feature which is consistent with the calculated wavelength-dependence of optical absorption, suggesting that the absolute intensity change of photocurrent is dominated by the plasmon-enhancement effects of gold nanostructure as similar to previous findings.\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e The existence of dip features at 1 \u003cem\u003eG\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e in Open photocurrent traces (\u003cb\u003eFig. S14\u003c/b\u003e) showcases that the current of photon-assisted transport in single-atom junctions is suppressed within the excitation wavelength ranging from 700 to 900 nm. In addition, the suppression ratio (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ec) as the indicator for photon-assisted transport shows an opposite tendency to photocurrent, suggesting that the current of photon-assisted transport is incoherent with the current by plasmon-induced transport.\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e Such a dependence of photon-assisted transport is a consequence of shifting the excitation energy window away for the electron modes of single-atom junctions, suggesting the transition of reflected states to transmitted states.\u003csup\u003e\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e\u003c/sup\u003e Meanwhile, the suppression presented in \u003cb\u003eFig. S15\u003c/b\u003e shows bias independence within a proper range (below 200 mV for our sample). The high bias voltage can reduce the formation probabilities and lifetime of single-atom junctions, resulting in a reversed photocurrent trend for Open and Close processes.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn this work, we observed the significant coherent oscillation induced photocurrent suppression in the single-atom junctions at room temperature, allowing the precise control of the coherent competition via atomic structure, while the coherent competition between absorption and emission pathways in the framework of photon-assisted transport reported in two-dimensional electron gas system is only capable to survive at the temperature of milliKelvin\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e. The oscillation results in a giant suppression of up to ~\u0026thinsp;50% photocurrent through single-atom junctions at room temperature, and the photon-assisted transport pathways are demonstrated to be not associated with the plasmon-induced transport pathway that we can separately modulate two mechanisms via controlling atomic structure. Our work demonstrates the capability of a.c. photocurrent measurement to extract structural information hidden by previous d.c. photoconductance measurement, which offers opportunities to investigate the real-time information of light-matter interactions at the scale of single-atom and future for single-molecule.\u003csup\u003e\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e, \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e\u003c/sup\u003e The capability of suppressing photon-assisted transport via atomic control opens a new route to functionalize room-temperature quantum devices and quantum plasmonic devices.\u003csup\u003e\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e, \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e \u003cb\u003eMCBJ experiments and photocurrent measurement of single-atomic junctions.\u003c/b\u003e \u003c/p\u003e \u003cp\u003eThe setup and beam path are depicted in \u003cb\u003eFig. S16\u003c/b\u003e. The details of the microfabrication of MCBJ chips can be found in our previous work.\u003csup\u003e\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e The break junction processes are controlled by pushing and pulling the pod underneath the MCBJ chip driven by a motor. The two-terminal of MCBJ chip is connected to the current input and voltage output ports of lock-in amplifier (MFLI, Zurich Instruments) which consists of a linear pre-amplifier and a lock-in loop. The 0 Hz current from the lock-in amplifier serves as the feedback signal for break junctions. The femtosecond laser (Chameleon Ultra Ⅱ, Coherent Inc) is chopped for a frequency of 983 Hz and sent to MCBJ chip in free space. The photocurrent at 983 Hz and flicker noise at 1023 Hz are recorded in real time. The femtosecond laser is tunable in the range of 680 to 1080 nm with a repetition frequency of 80 MHz. The diameter of laser beam used in measurement is approximately 100 \u0026micro;m. Consequently, the power density for measurement is approximately 7.36 W/cm\u003csup\u003e2\u003c/sup\u003e (corresponding to peak power density of 2.3\u0026times;10\u003csup\u003e6\u003c/sup\u003e W/cm\u003csup\u003e2\u003c/sup\u003e) for per mW excitation.\u003c/p\u003e\n\u003ch3\u003ePhotoconductance calculation\u003c/h3\u003e\n\u003cp\u003eThe photoconductance of quantum point contacts is calculated through the transport model described in the main text for Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The detailed analytical derivation and formulation of the model are discussed in the supplementary information. In the linear regime where only one photon is absorbed or emitted, the overall photoconductance can be written as:\u003c/p\u003e\u003cp\u003e\u003cimg 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\" height=\"199\" width=\"584\"\u003e\u003c/p\u003e\n\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eElectromagnetic simulation\u003c/h2\u003e \u003cp\u003eThe absorption spectrum of the nanoelectrodes pair in the nano-lithographic MCBJ chip is obtained by the commercial software COMSOL Multiphysics based on the finite element method. The geometry of MCBJ chip was inferred from SEM images (\u003cb\u003eFig. S16b\u003c/b\u003e), We only integrate the absorption throughout the center junction part of MCBJ to reflect the absorption of the atomic junction.\u003c/p\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003ch2\u003eCompeting interests\u003c/h2\u003e \u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e \u003ch2\u003eAuthor contributions\u003c/h2\u003e \u003cp\u003eW. H. supervised the project. W. H., L. C. and J. L. originally conceived the concept and designed the experiments. H. Z., L. C. and J. S. designed and constructed the setup with the support of H. L. Z. Q., Y. J., J. Z. and J. L. prepared the MCBJ chips. L. C., H. Z. and Z. Q. performed the photocurrent measurements. H. Z. and Y. C. performed photoluminescence measurements. L. C. developed the data analysis method and analyzed the results. J. Y., J.-R. Z. carried out the calculations. L. C. prepared the manuscript with input from other authors.\u003c/p\u003e\u003ch2\u003eAcknowledgments\u003c/h2\u003e \u003cp\u003eThis work was supported by the National Key Research and Development Program of China (2024YFA1208103), the Natural Science Foundation of China (22325303, 22173075, 22272140, 21933012), the Fujian Provincial Department of Science and Technology (2023H6002). We also acknowledge the support from the ultra-precision lab in IKKEM for offering the experimental platforms.\u003c/p\u003e\u003ch2\u003eData availability\u003c/h2\u003e \u003cp\u003eAll data that support the findings of this study are available from the corresponding author upon reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eBaumberg JJ, Aizpurua J, Mikkelsen MH (2019) Smith D. R. Extreme nanophotonics from ultrathin metallic gaps. 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Nat Rev Mater 8:668\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"nature-portfolio","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"","title":"Nature Portfolio","twitterHandle":"","acdcEnabled":false,"dfaEnabled":false,"editorialSystem":"ejp","reportingPortfolio":"","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-6367654/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6367654/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eControl of light-driven current at the nanoscale is essential for optoelectronics, energy transfer, and information processing, and the single-atom junctions preserving electron coherence serves as a model system with ultimate size to investigate and manipulate light-driven transport. However, the light-driven coherent transport through the single-atom junctions remains elusive due to the challenge of controlling their atomic topography at room temperature. Here, we demonstrate a photocurrent oscillation from photon-assisted coherent transport in single-atom junctions by controlling the atomic structure using the mechanically controllable break junction technique at ambient condition. Such an oscillation results in a giant suppression ratio of up to ~\u0026thinsp;50% of the collective photocurrent, which disentangle the coherent interplay between two opposite transport pathways of photon-induced absorption and emission from the plasmon-induced hot-electron transport. Our findings offer an atomically precise strategy to control light-driven transport and open a new route toward atomic-scale high-frequency optoelectronics.\u003c/p\u003e","manuscriptTitle":"Coherent oscillation in photocurrent through single-atom junctions at room temperature","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-03 09:24:05","doi":"10.21203/rs.3.rs-6367654/v1","editorialEvents":[],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"nature-communications","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"NCOMMS","sideBox":"Learn more about [Nature Communications](http://www.nature.com/ncomms/)","snPcode":"","submissionUrl":"https://mts-ncomms.nature.com/","title":"Nature Communications","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature Communications","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"cb663f72-de1d-40e9-a8b3-e5b4055ff2f4","owner":[],"postedDate":"June 3rd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":48251475,"name":"Physical sciences/Nanoscience and technology/Nanoscale devices/Molecular electronics"},{"id":48251476,"name":"Physical sciences/Nanoscience and technology/Nanoscale devices/Nanophotonics and plasmonics"}],"tags":[],"updatedAt":"2025-06-03T09:24:05+00:00","versionOfRecord":[],"versionCreatedAt":"2025-06-03 09:24:05","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6367654","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6367654","identity":"rs-6367654","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}