Fermiology of possible topological superconductor Tl0.5Bi2Te3 derived from hole-doped topological insulator

TL;DR

This study uses angle-resolved photoemission spectroscopy to analyze the electronic structure of Tl0.5Bi2Te3, a candidate topological superconductor, revealing its Fermi surface topology and potential for realizing topological superconductivity.

Contribution

It provides detailed experimental insights into the Fermi surface and surface states of Tl0.5Bi2Te3, supporting its role as a platform for topological superconductivity.

Findings

Bulk Fermi surface consists of three-dimensional hole pockets.

Dirac-cone surface state is well isolated from bulk bands.

Surface chemical potential is tunable across the band gap.

Abstract

We have performed angle-resolved photoemission spectroscopy on Tl0.5Bi2Te3, a possible topological superconductor derived from Bi2Te3. We found that the bulk Fermi surface consists of multiple three-dimensional hole pockets surrounding the Z point, produced by the direct hole doping into the valence band. The Dirac-cone surface state is well isolated from the bulk bands, and the surface chemical potential is variable in the entire band-gap range. Tl0.5Bi2Te3 thus provides an excellent platform to realize two-dimensional topological superconductivity through a proximity effect from the superconducting bulk. Also, the observed Fermi-surface topology provides a concrete basis for constructing theoretical models for bulk topological superconductivity in hole-doped topological insulators.