Spin-polarized tunneling current through a thin film of topological insulator in a parallel magnetic field

TL;DR

This paper investigates how a parallel magnetic field influences the tunneling conductance and spin polarization of surface states in ultra-thin topological insulator films, revealing controllable spin-polarized currents.

Contribution

It introduces a model for tunneling conductance in topological insulator films under parallel magnetic fields, highlighting the magnetic control of spin-polarized tunneling.

Findings

Tunneling conductance depends on the magnetic field due to shifted Fermi circles.

Spin polarization of tunneling current can be tuned by magnetic field B_y.

Unusual magnetic field dependence of conductance observed.

Abstract

We calculate the tunneling conductance \sigma between the surface states on the opposite sides of the ultra-thin film of a topological insulator in a parallel magnetic field B_y. The parallel magnetic produces a relative shift of the in-plane momenta of the two surfaces states. An overlap between the shifted Fermi circles and their spin structure define an unusual dependence of the tunneling conductance \sigma(B_y) on the magnetic field. Because the spin of the electronic surface states in topological insulators is locked with momentum, the spin-polarization of the tunneling current can be controlled by magnetic field B_y.