Topological electronic structure and electronic nematicity in candidate kagome superconductors, ATi$_{3}$Bi$_{5}$ (A = Rb, Cs)

TL;DR

This paper reviews the topological electronic properties and electronic nematicity in the newly discovered kagome superconductors ATi$_{3}$Bi$_{5}$ (A=Rb,Cs), highlighting their unique features compared to vanadium-based counterparts and discussing recent experimental and theoretical advances.

Contribution

It provides a comprehensive overview of the electronic structure, nematicity, and potential superconductivity in ATi$_{3}$Bi$_{5}$, emphasizing their distinct non-CDW nature and topological properties.

Findings

ATi$_{3}$Bi$_{5}$ exhibits non-trivial band topology.

No evidence of charge density wave in ATi$_{3}$Bi$_{5}$.

Presence of electronic nematicity and potential superconductivity.

Abstract

The newly discovered family of titanium-based kagome metals, ATi$_{3}$Bi$_{5}$ (where A can be Rb or Cs), has been found to exhibit non-trivial band topology and fascinating electronic instabilities, including electronic nematicity and potential bulk superconductivity. Distinct from their vanadium-based counterparts (AV$_{3}$Sb$_{5}$), which display a charge density wave (CDW) phase that already breaks rotational symmetry, ATi$_{3}$Bi$_{5}$ shows no evidence of CDW, providing a unique platform to study nematicity in its pure form and its interplay with other correlated quantum phenomena, such as superconductivity. In this review, we highlight recent progress in both experimental and theoretical research on ATi$_{3}$Bi$_{5}$ and discuss the unresolved questions and challenges in this burgeoning field.