Universal sublinear resistivity in vanadium kagome materials hosting charge density waves

Abstract The recent discovery of a charge density (CDW) state in ScV6Sn6 at TCDW = 91 K offers new opportunities to understand the origins of electronic instabilities in topological kagome systems. By comparing to the isostructural non-CDW compound LuV6Sn6, we unravel interesting electrical transport properties in ScV6Sn6, above and below the charge ordering temperature. We observed that by applying a magnetic field along the a axis, the temperature behavior of the longitudinal resistivity in ScV6Sn6 changes from metal-like to insulator-like above the CDW transition. We show that in the charge ordered state ScV6Sn6 follows the Fermi liquid behavior while above that, it transforms into a non-Fermi liquid phase in which the resistivity varies sublinearly over a broad temperature range. The sublinear resistivity, which scales by T3/5 is a common feature among other vanadium-containing kagome compounds exhibiting CDW states such as KV3Sb5, RbV3Sb5, and CsV3Sb5. By contrast, the non-Fermi liquid behavior does not occur in LuV6Sn6. We explain the T3/5 universal scaling behavior from the Coulomb scattering between Dirac electrons and Van Hove singularities; common features in the electronic structure of kagome materials. Finally, we show anomalous Hall-like behavior in ScV6Sn6 below TCDW, which is absent in the Lu compound. Comparing the transport properties of ScV6Sn6 and LuV6Sn6 is valuable to highlight the impacts of the unusual CDW in the Sc compound.