Chaotic Quantum Transport near the Charge Neutrality Point in Inverted Type-II InAs/GaSb Field-Effect Transistors

TL;DR

This paper investigates quantum transport phenomena near the charge neutrality point in InAs/GaSb transistors, revealing conductance minima, quantum Hall states, and chaotic behavior under high magnetic fields, advancing understanding of topological insulator systems.

Contribution

It reports the discovery of a circular conductivity law indicating chaotic quantum transport in InAs/GaSb transistors near the charge neutrality point.

Findings

Conductance minimum of ~4e^2/h at CNP with semi-log temperature dependence

Observation of well-developed integer quantum Hall states in electron and hole regimes

Detection of a circular conductivity law indicating chaotic quantum transport

Abstract

We present here our recent quantum transport results around the charge neutrality point (CNP) in a type-II InAs/GaSb field-effect transistor. At zero magnetic field, a conductance minimum close to 4e^2/h develops at the CNP and it follows semi-logarithmic temperature dependence. In quantized magnetic (B) fields and at low temperatures, well developed integer quantum Hall states are observed in the electron as well as hole regimes. Quantum transport shows noisy-like behavior around the CNP at extremely high B fields. Surprisingly, when the diagonal conductivity \sigma_{xx} is plotted against the Hall conductivity \sigma_{xy}, a circular conductivity law is discovered, suggesting a chaotic quantum transport behavior.