Anisotropic magnetism and electronic properties of the kagome metal SmV6Sn6

Abstract

Kagome magnets are expected to feature emergent properties due to the interplay among geometry, magnetism, electronic correlation, and band topology. The magnetism and topological electronic states can be tuned via the rare-earth engineering in ${R\mathrm{V}}_{6}{\mathrm{Sn}}_{6}$ kagome metals, where $R$ is a rare-earth element. Herein, we present the synthesis and characterization of ${\mathrm{SmV}}_{6}{\mathrm{Sn}}_{6}$, a metal with two-dimensional kagome nets of vanadium and a frustrated triangular Sm lattice. Some of the Sm atoms are shifted from the normal $R$ positions by $c/2$ along the $c$ axis. Magnetic measurements reveal obvious anisotropy, where the easy magnetic axis is within the $ab$ plane. Electronic transport shows multiband behaviors below 200 K. Density functional theory calculations find that the electronic structure of ${\mathrm{SmV}}_{6}{\mathrm{Sn}}_{6}$ hosts flat bands, Dirac cones, and saddle points arising from the V $3d$ electrons near the Fermi level. No evidence for the existence of a charge density wave or magnetic order down to 2 K can be observed. Thus, ${\mathrm{SmV}}_{6}{\mathrm{Sn}}_{6}$ can be viewed as a modest disordered derivative of the ${R\mathrm{V}}_{6}{\mathrm{Sn}}_{6}$ structure, in which the disordered rare-earth ions can suppress the magnetic order and charge density wave in the ${R\mathrm{V}}_{6}{\mathrm{Sn}}_{6}$ kagome family.