Electrically controllable spin filtering in antiferromagnetic topological insulator tunneling junctions

¹ College of Computer and Information Engineering, Central South University of Forestry and Technology Changsha 410004, PRC

^(a) genhualiu@csuft.edu.cn (corresponding author)

Received: 29 July 2021
Accepted: 20 January 2022

Abstract

We study the surface-state band structure and transport property for an antiferromagnetic MnBi₂Te₄ film with an external electric field vertical to its top surface. The electric field can reduce the gap of surface states induced by a finite-size effect, and restore the chirality of surface states, which may be beneficial to the realization of an axion state. We also demonstrate that an adjustable electric field can not only switch between the spin-up and spin-down electron channels to realize spin filtering, but also close all the electronic channels to realize on-off current in an antiferromagnetic MnBi₂Te₄ thin film with two junctions.