Transport properties of a 3D topological insulator based on a strained high mobility HgTe film

TL;DR

This study explores the magnetotransport properties of strained HgTe thin films, demonstrating the tunability of surface and bulk states and confirming its topological insulator nature with gapless surface states.

Contribution

It provides detailed experimental analysis of the transport behavior in strained HgTe, highlighting the ability to tune Fermi energy across different electronic states and confirming topological insulator characteristics.

Findings

High mobility of 4x10^5 cm^2/Vs in HgTe layers

Fermi energy tunable across valence, Dirac surface, and conduction bands

Confirmation of gapless surface states in strained HgTe

Abstract

We investigated the magnetotransport properties of strained, 80nm thick HgTe layers featuring a high mobility of mu =4x10^5 cm^2/Vs. By means of a top gate the Fermi-energy is tuned from the valence band through the Dirac type surface states into the conduction band. Magnetotransport measurements allow to disentangle the different contributions of conduction band electrons, holes and Dirac electrons to the conductivity. The results are are in line with previous claims that strained HgTe is a topological insulator with a bulk gap of ~15meV and gapless surface states.