Mapping the phase diagram of the quantum anomalous Hall and topological Hall effects in a dual-gated magnetic topological insulator heterostructure

TL;DR

This study maps the phase diagram of topological and quantum anomalous Hall effects in magnetic topological insulators using dual gating, revealing the influence of gate voltages on topological phenomena and chiral magnetic textures.

Contribution

It introduces a combined experimental and theoretical approach to control and understand topological Hall and quantum anomalous Hall effects via gating in magnetic topological insulators.

Findings

Identification of gate-dependent phase regions for Hall effects

Theoretical model matches experimental phase diagram

Evidence for topological Hall effect in the system

Abstract

We use magnetotransport in dual-gated magnetic topological insulator heterostructures to map out a phase diagram of the topological Hall and quantum anomalous Hall effects as a function of the chemical potential (primarily determined by the back gate voltage) and the asymmetric potential (primarily determined by the top gate voltage). A theoretical model that includes both surface states and valence band quantum well states allows the evaluation of the variation of the Dzyaloshinskii-Moriya interaction and carrier density with gate voltages. The qualitative agreement between experiment and theory provides strong evidence for the existence of a topological Hall effect in the system studied, opening up a new route for understanding and manipulating chiral magnetic spin textures in real space.