CsV$_3$Sb$_5$: a $\mathbb{Z}_2$ topological kagome metal with a superconducting ground state

TL;DR

CsV$_3$Sb$_5$ is a newly identified $ ext{Z}_2$ topological kagome metal exhibiting bulk superconductivity at 2.5K, with its electronic structure characterized by ARPES and DFT, revealing Dirac crossings and potential unconventional superconductivity.

Contribution

This study reports the discovery of superconductivity and topological properties in CsV$_3$Sb$_5$, providing insights into its electronic structure and correlation effects.

Findings

Bulk superconductivity at T$_c$ = 2.5K

Identification of $ ext{Z}_2$ topological metallic state

Presence of Dirac crossings near the Fermi level

Abstract

Recently discovered alongside its sister compounds KV$_3$Sb$_5$ and RbV$_3$Sb$_5$, CsV$_3$Sb$_5$ crystallizes with an ideal kagome network of vanadium and antimonene layers separated by alkali metal ions. This work presents the electronic properties of CsV$_3$Sb$_5$, demonstrating bulk superconductivity in single crystals with a T$_{c} = 2.5$K. The normal state electronic structure is studied via angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT), which categorize CsV$_3$Sb$_5$ as a $\mathbb{Z}_2$ topological metal. Multiple protected Dirac crossings are predicted in close proximity to the Fermi level ($E_F$), and signatures of normal state correlation effects are also suggested by a high temperature charge density wave-like instability. The implications for the formation of unconventional superconductivity in this material are discussed.