Quantum Hall Effect in Thin Films of Three-Dimensional Topological Insulators

TL;DR

This paper demonstrates that thin films of three-dimensional topological insulators with an exchange field can realize the quantum Hall effect without Landau levels, showing a unique phase diagram distinct from traditional systems.

Contribution

It introduces a model where 3D topological insulator thin films mimic the Haldane model, revealing a novel quantum Hall effect mechanism without Landau levels.

Findings

Quantum Hall effect realized without Landau levels in 3DTI thin films.

Exchange field acts as staggered fluxes, inducing QHE.

Unique phase diagram under magnetic field differs from traditional systems.

Abstract

We show that a thin film of a three-dimensional topological insulator (3DTI) with an exchange field is a realization of the famous Haldane model for quantum Hall effect (QHE) without Landau levels. The exchange field plays the role of staggered fluxes on the honeycomb lattice, and the hybridization gap of the surface states is equivalent to alternating on-site energies on the AB sublattices. A peculiar phase diagram for the QHE is predicted in 3DTI thin films under an applied magnetic field, which is quite different from that either in traditional QHE systems or in graphene.