Gate voltage controlled electronic transport through a ferromagnet/normal/ferromagnet junction on the surface of a topological insulator

TL;DR

This paper studies how gate voltage influences electronic transport in a topological insulator junction with ferromagnetic contacts, revealing oscillatory conductance, tunable spintronic effects, and large magnetoresistance.

Contribution

It demonstrates gate-controlled conductance oscillations and negative magnetoresistance in a topological insulator junction, highlighting potential for spintronic device applications.

Findings

Conductance oscillates with normal segment width and gate voltage.

Gate voltage can modulate conductance like a spin field-effect transistor.

Magnetoresistance ratio can be very large or negative due to anomalous transport.

Abstract

We investigate the electronic transport properties of a ferromagnet/normal/ferromagnet junction on the surface of a topological insulator with a gate voltage exerted on the normal segment. It is found that the conductance oscillates with the width of normal segment and gate voltage, and the maximum of conductance gradually decreases while the minimum of conductance approaches zero as the width increases. The conductance can be controlled by tuning the gate voltage like a spin field-effect transistor. It is found that the magnetoresistance ratio can be very large, and can also be negative owing to the anomalous transport. In addition, when there exists a magnetization component in the surface plane, it is shown that only the component parallel to the junction interface has an influence on the conductance.