Electrically Tunable Magnetism in Magnetic Topological Insulators

TL;DR

This paper predicts that electric fields can control ferromagnetism in magnetic topological insulators, enabling phase transitions and potential applications in spintronics and memory devices.

Contribution

It introduces a method to electrically tune magnetism and induce magnetic phase transitions in magnetic topological insulators, with implications for device applications.

Findings

Electric field reduces band inversion and magnetic susceptibility.

Electric field can induce transition from ferromagnetism to paramagnetism.

Proposes a topological transistor device with electric field-controlled edge states.

Abstract

The external controllability of the magnetic properties in topological insulators would be important both for fundamental and practical interests. Here we predict the electric-field control of ferromagnetism in a thin film of insulating magnetic topological insulators. The decrease of band inversion by the application of electric fields results in a reduction of magnetic susceptibility, and hence in the modification of magnetism. Remarkably, the electric field could even induce the magnetic quantum phase transition from ferromagnetism to paramagnetism. We further propose a topological transistor device in which the dissipationless charge transport of chiral edge states is controlled by an electric field. In particular, the field-controlled ferromagnetism in magnetic topological insulator can be used for voltage based writing of magnetic random access memories in magnetic tunnel junctions. The simultaneous electrical control of magnetic order and chiral edge transport in such devices may lead to electronic and spintronic applications for topological insulators.