Universal sublinear resistivity in vanadium kagome materials hosting charge density waves*

The recent discovery of a charge density (CDW) state in ScV₆Sn₆ at T_CDW = 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 T_CDW. 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 T^3/5 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 T^3/5 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 T_CDW, 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.