Effect of magnetic field on a magnetic topological insulator film with structural inversion asymmetry

TL;DR

This paper explores how magnetic fields influence ultrathin magnetic topological insulator films with structural inversion asymmetry, revealing phase stability, induced nontrivial phases, and fractional resistance plateaus through analytical and simulation methods.

Contribution

It introduces a phase diagram, calculates Landau levels analytically, and simulates transport behavior, uncovering new phases and resistance phenomena in magnetic topological insulator films.

Findings

Quantum anomalous Hall phase persists under increasing magnetic field.

Magnetic field induces a nontrivial phase similar to quantum spin Hall effect.

Fractional resistance plateaus observed due to edge state coupling.

Abstract

The effect of magnetic field on an ultrathin magnetic topological insulator film with structural inversion asymmetry is investigated. We introduce the phase diagram, calculate the Landau-level spectrum analytically and simulate the transport behavior in Landauer-B\"uttiker formalism. The quantum anomalous Hall phase will survive increasing magnetic field. Due to the two spin polarized zero modes of Landau levels a nontrivial phase similar with quantum spin Hall effect can be induced by magnetic field which is protected by structural inversion symmetry. Some exotic longitudinal and Hall resistance plateaus with fractional values are also found in a six terminal Hall bar, arising from the coupling between edge states due to inverted energy band and Landau levels.