Discovery of two families of VSb-based compounds with V-kagome lattice

TL;DR

This paper reports the discovery and characterization of two new V-kagome lattice compounds, revealing their structures, electronic properties, and the absence of superconductivity up to high pressures, thus advancing the understanding of V-based kagome materials.

Contribution

The study introduces two novel V-kagome compounds with distinct stacking and symmetry, providing detailed structural, electronic, and transport property analyses, and contrasting their behaviors with related materials.

Findings

Both compounds are nonmagnetic metals with carrier concentrations around 10^21 cm^-3.

No superconductivity observed above 0.3 K up to 46 GPa in CsV8Sb12.

CsV8Sb12 exhibits a quasi-two-dimensional electronic structure with C2 symmetry and lacks van Hove singularities near the Fermi level.

Abstract

We report the structure and physical properties of two newly-discovered compounds AV8Sb12 and AV6Sb6 (A = Cs, Rb), which have C2 (space group: Cmmm) and C3 (space group: R-3m) symmetry, respectively. The basic V-kagome unit is present in both compounds, but stacking differently. A V2Sb2 layer is sandwiched between two V3Sb5 layers in AV8Sb12, altering the V-kagome lattice and lowering the symmetry of kagome layer from hexagonal to orthorhombic. In AV6Sb6, the building block is a more complex slab made up of two half-V3Sb5 layers that are intercalated by Cs cations along the c-axis. Transport property measurements demonstrate that both compounds are nonmagnetic metals, with carrier concentrations at around 1021cm-3. No superconductivity has been observed in CsV8Sb12 above 0.3 K under in-situ pressure up to 46 GPa. In contrast to CsV3Sb5, theoretical calculations and angle-resolved photoemission spectroscopy (ARPES) reveal a quasi-two-dimensional electronic structure in CsV8Sb12 with C2 symmetry and no van Hove singularities near the Fermi level. Our findings will stimulate more research into V-based kagome quantum materials.