Pressure induced Superconductivity and location of Fermi energy at Dirac point in BiSbTe3

TL;DR

This study demonstrates pressure-induced superconductivity in BiSbTe3, a topological insulator, with the Dirac point located at the Fermi level, and explores its electronic structure and transport properties.

Contribution

It reports the emergence of superconductivity under pressure in BiSbTe3 and precisely locates the Dirac point at the Fermi level using ARPES, providing insights into pressure effects on topological insulators.

Findings

Superconductivity appears at 8 GPa with Tc ~2.5 K.

Tc increases with pressure, reaching ~3.3 K at 14 GPa.

Dirac point is located exactly at the Fermi level in BiSbTe3.

Abstract

We have grown single-crystal BiSbTe3 3D TI sample and studied structural, TE as well as pressure dependent magneto-transport properties. Large positive Seebeck coefficient confirmed the p-type nature of BiSbTe3, which is consistent with Hall measurement. We have also studied the electronic band structure using Laser-based ARPES, which revealed the existence of a Dirac-cone like metallic surface state in BiSbTe3 with a Dirac Point situated exactly at the Fermi level. Additionally, superconductivity emerges under pressure of 8 GPa with a critical temperature of ~2.5 K. With further increase of pressure, the superconducting transition temperature (Tc) increases and at 14 GPa it shows the maximum Tc (~3.3 K).