A density-wave-like transition in the polycrystalline V3Sb2 sample with bilayer kagome lattice

Recently, transition-metal-based kagome metals have aroused much research interest as a novel platform to explore exotic topological quantum phenomena. Here we report on the synthesis, structure, and physical properties of a bilayer kagome lattice compound V3Sb2. The polycrystalline V3Sb2 samples were synthesized by conventional solid-state-reaction method in a sealed quartz tube at temperatures below 850 degree Celsius. Measurements of magnetic susceptibility and resistivity revealed consistently a density-wave-like transition at Tdw - 160 K with a large thermal hysteresis, even though some sample-dependent behaviors are observed presumably due to the different preparation conditions. This transition can be suppressed completely by applying hydrostatic pressures of about 1.8 GPa, but no sign of superconductivity is observed down to 1.5 K in the vicinity of putative quantum critical point of the density-wave order. The specific-heat measurements reveal a relatively large Sommerfeld coefficient 18.5 mJ/mol-K2, confirming the metallic ground state with moderate electronic correlations. Density functional theory calculations indicate that V3Sb2 shows a non-trivial topological crystalline property. Thus, our study makes V3Sb2 a new candidate of metallic kagome compound to study the interplay between density-wave-order, nontrivial band topology, and possible superconductivity.