Large Topological Magnetic Optical Effects and Imaging of Antiferromagnetic Octupole Domains of an Altermagnet-like Weyl Semimetal Eu2Ir2O7

Large Topological Magnetic Optical Effects and Imaging of Antiferromagnetic Octupole Domains of an Altermagnet-like Weyl Semimetal Eu2Ir2O7 | 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 Large Topological Magnetic Optical Effects and Imaging of Antiferromagnetic Octupole Domains of an Altermagnet-like Weyl Semimetal Eu 2 Ir 2 O 7 Liang Wu, Xingyu Han, Xiaoran Liu, M. Kareev, Jak Chakhalian This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6521355/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 Pyrochlore iridates have attracted significant interest due to their complex phase behavior arising from the interplay among electron correlations, quantum metric in flat bands, geometrically frustrated lattices, and topology induced by strong spin-orbit coupling. In this study, we focus on Eu2Ir2O7 thin films oriented along the (111) crystallographic direction. This quantum material, identified as an antiferromagnetic Weyl semimetal, exhibits a large anomalous Hall effect in transport experiments. Here we employ optical circular dichroism microscopy, to directly image ferroic octupole order and resolve all-in–all-out and all-out–all-in antiferromagnetic domains below the Néel temperature. Remarkably, despite the absence of a detectable net magnetic moment at zero applied magnetic field, we detected a large magnetic circular dichroism signal (∼ 10−4 ) and Kerr effect (∼ 10−4 radians) in zero magnetic field attributable to Berry curvature effects from Weyl nodes. Eu2Ir2O7 is a non-collinear magnet with vanishing net moment and magnetic octupole order, similar to the recently proposed collinear d-wave altermagnets, allowing for magneto-optical responses and anomalous Hall effect. This finding likely represents the first demonstration of magnetic circular dichroism and Kerr effect in a topologically non-trivial quantum antiferromagnet with a vanishing net magnetization. Our work opens up the possibility of ultrafast domain switching in the terahertz frequency and the domain wall dynamics in the magnetic Weyl systems, which establishes the foundation for topological antiferromagnetic spintronics. Physical sciences/Materials science/Condensed-matter physics/Magnetic properties and materials Physical sciences/Materials science/Condensed-matter physics/Topological matter Physical sciences/Materials science/Condensed-matter physics/Spintronics Full Text Additional Declarations There is NO Competing Interest. 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-6521355","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":458559925,"identity":"5c0f3d7b-23d9-457b-8713-1807d7117d8b","order_by":0,"name":"Liang Wu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3UlEQVRIiWNgGAWjYBACPmYog3EGA+MDIM3DR0gLG5IWZgOQFjaCWuAsCQY2CVQRXFrYmZ89/Np2mIF5do9Z5dccOxk2BuaHj27gdRibubEsUAvjnDNmt2W3JQMdxmZsnIPfL2bSktuAWmbkmN2W3MYM1MLDJo1fC/s3uJZiyW31xGjhMZP8CNXCCGQQpaVMmvFfOg/jjLRiacZtx3mAvsPvF37+49skf5yxljOckbzx489t1fb87M0PH+PTAgLMPMAYNGyAMIAkAeUgwPgDSMjDGKNgFIyCUTAK0AEA0xQ7XQDctUwAAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0003-1696-7809","institution":"University of Pennsylvania","correspondingAuthor":true,"prefix":"","firstName":"Liang","middleName":"","lastName":"Wu","suffix":""},{"id":458559926,"identity":"aa36f8ca-e751-46bc-a5c0-331d71bc0ef2","order_by":1,"name":"Xingyu Han","email":"","orcid":"https://orcid.org/0000-0001-6775-4171","institution":"University of Pennsylvania","correspondingAuthor":false,"prefix":"","firstName":"Xingyu","middleName":"","lastName":"Han","suffix":""},{"id":458559927,"identity":"919bce03-5f62-4eae-aa74-0ef4db6b1a8d","order_by":2,"name":"Xiaoran Liu","email":"","orcid":"https://orcid.org/0000-0003-0938-6109","institution":"Institute of Physics, CAS","correspondingAuthor":false,"prefix":"","firstName":"Xiaoran","middleName":"","lastName":"Liu","suffix":""},{"id":458559928,"identity":"b42514ce-94d6-4f78-b8f0-57d1f5dfad74","order_by":3,"name":"M. 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In this study, we focus on Eu2Ir2O7 thin films oriented along the (111) crystallographic direction. This quantum material, identified as an antiferromagnetic Weyl semimetal, exhibits a large anomalous Hall effect in transport experiments. Here we employ optical circular dichroism microscopy, to directly image ferroic octupole order and resolve all-in–all-out and all-out–all-in antiferromagnetic domains below the Néel temperature. Remarkably, despite the absence of a detectable net magnetic moment at zero applied magnetic field, we detected a large magnetic circular dichroism signal (∼ 10−4 ) and Kerr effect (∼ 10−4 radians) in zero magnetic field attributable to Berry curvature effects from Weyl nodes. Eu2Ir2O7 is a non-collinear magnet with vanishing net moment and magnetic octupole order, similar to the recently proposed collinear d-wave altermagnets, allowing for magneto-optical responses and anomalous Hall effect. This finding likely represents the first demonstration of magnetic circular dichroism and Kerr effect in a topologically non-trivial quantum antiferromagnet with a vanishing net magnetization. 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