Chemical tuning of electronic and transport properties of the Bi-Se-Te family of topological insulators

TL;DR

This study uses ARPES to show how chemical substitution in Bi-Se-Te topological insulators tunes their electronic properties, revealing a transition from metallic to semiconducting behavior and highlighting the dominance of surface states at high Te levels.

Contribution

It demonstrates how varying Te content in BiSeTe modifies electronic structure and transport properties, providing insights into controlling topological surface states.

Findings

Increasing Te lowers the chemical potential and Dirac point binding energy.

Higher Te reduces bulk density of states and changes resistivity temperature dependence.

At high Te, resistivity saturates, indicating dominant surface state conduction.

Abstract

We use laser-based Angle-Resolved Photoemission Spectroscopy (ARPES) to study how chemical substitution modifies the electronic properties of the Bi2(Se{1-x}Tex)3 (BiSeTe) family of topological insulators. We find that increasing the Te content lowers the chemical potential, leading to a decrease in the binding energy of the Dirac point and a reduction in the density of states originating from the bulk band. This reduction leads to a transition from metallic to semiconducting temperature dependence of the resistivity. For the highest Te concentration, the resistivity nearly saturates at the lowest temperatures. The presence of this plateau indicates that metallic topological surface states dominate the conductance, opening the possibility of studying their transport properties.