Unusual magnetoresistance in a topological insulator with a single ferromagnetic barrier

TL;DR

This paper reports a novel magnetoresistance effect in topological insulators with a single ferromagnetic barrier, showing a giant 800% change in current driven by magnetization orientation, promising for low-power electronic applications.

Contribution

It introduces a new magnetoresistance mechanism in topological insulators with a single ferromagnetic barrier, differing from conventional multi-layer devices.

Findings

Giant magnetoresistance up to 800% at room temperature.

Transmission current drastically changes with 90-degree magnetization rotation.

Potential for sharp, low-power electronic switching.

Abstract

Tunneling surface current through a thin ferromagnetic barrier in a three-dimensional topological insulator is shown to possess an extraordinary response to the orientation of barrier magnetization. In contrast to conventional magnetoresistance devices that are sensitive to the relative alignment of two magnetic layers, a drastic change in the transmission current is achieved by a single layer when its magnetization rotates by 90 degrees. Numerical estimations predict a giant magnetoresistance as large as 800 % at room temperature and the proximate exchange interaction of 40 meV in the barrier. When coupled with electrical control of magnetization direction, this phenomenon may be used to enhance the gating function with potentially sharp turn-on/off for low power applications.