Electronic properties of the topological kagome metals YV6Sn6 and GdV6Sn6

The synthesis and characterization of vanadium-based kagome metals ${\mathrm{YV}}_{6}{\mathrm{Sn}}_{6}$ and ${\mathrm{GdV}}_{6}{\mathrm{Sn}}_{6}$ are presented. X-ray diffraction, magnetization, magnetotransport, and heat capacity measurements reveal an ideal kagome network of V ions coordinated by Sn and separated by triangular lattice planes of rare-earth ions. The onset of low-temperature magnetic order of Gd spins is detected in ${\mathrm{GdV}}_{6}{\mathrm{Sn}}_{6}$ and is suggested to be noncollinear, while V ions in both compounds remain nonmagnetic. Density functional theory calculations are presented modeling the band structures of both compounds, which can be classified as ${\mathbb{Z}}_{2}$ topological metals in the paramagnetic state. Both compounds exhibit high mobility, multiband transport and present an interesting platform for controlling the interplay between magnetic order associated with the $R$-site sublattice and nontrivial band topology associated with the V-based kagome network. Our results invite future exploration of other $R{\mathrm{V}}_{6}{\mathrm{Sn}}_{6}$ ($R$ = rare earth) variants where this interplay can be tuned via $R$-site substitution.