High pressure transport properties of the topological insulator Bi2Se3

TL;DR

This study investigates how high pressure affects the structural and electrical transport properties of the topological insulator Bi2Se3, revealing pressure-induced transitions from insulating to metallic states and unusual magnetoresistance behavior.

Contribution

It provides detailed experimental insights into pressure-driven phase transitions and transport property changes in Bi2Se3, a topological insulator, under high pressure conditions.

Findings

Pressure induces a transition from insulating to metallic behavior.

Magnetoresistance shows positive at low fields and negative at high fields.

Pressure below 8 GPa reduces bulk conductivity without chemical doping.

Abstract

We report x-ray diffraction, electrical resistivity, and magnetoresistance measurements on Bi2Se3 under high pressure and low temperature conditions. Pressure induces profound changes in both the room temperature value of the electrical resistivity as well as the temperature dependence of the resistivity. Initially, pressure drives Bi2Se3 towards increasingly insulating behavior and then, at higher pressures, the sample appears to enter a fully metallic state coincident with a change in the crystal structure. Within the low pressure phase, Bi2Se3 exhibits an unusual field dependence of the transverse magnetoresistance that is positive at low fields and becomes negative at higher fields. Our results demonstrate that pressures below 8 GPa provide a non-chemical means to controllably reduce the bulk conductivity of Bi2Se3.