Unusual 5f magnetism in new kagome material UV6Sn6

Abstract

Materials in the family RV6Sn6 (R = rare earth) provide a unique platform to investigate the interplay between local moments from R layers and nonmagnetic vanadium kagome layers. Yet, the investigation of actinide members remains scarce. Here we report the synthesis of UV6Sn6 single crystals through the self-flux technique. Physical property measurements reveal two uranium-driven antiferromagnetic transitions at TN1 = 29 K and TN2 = 24 K, a complex field-temperature phase diagram, and unusual negative domain-wall magnetoresistance. Specific heat and angle-resolved photoemission spectroscopy measurements show a moderate f-electron enhancement to the density of states at the Fermi level (EF), whereas our band structure calculations place the vanadium flat bands 0.25 eV above EF. These findings point to a materials opportunity to expand the uranium 166 family with the goal of enhancing correlations by tuning 5f and 3d flat bands to EF.