Spin-related tunneling through a nanostructured electric-magnetic barrier on the surface of a topological insulator.

Zhenhua Wu,Jun Li

doi:10.1186/1556-276x-7-90

Abstract

We investigate quantum tunneling through a single electric and/or magnetic barrier on the surface of a three-dimensional topological insulator. We found that (1) the propagating behavior of electrons in such system exhibits a strong dependence on the direction of the incident electron wavevector and incident energy, giving the possibility to construct a wave vector and/or energy filter; (2) the spin orientation can be tuned by changing the magnetic barrier structure as well as the incident angles and energies.PACS numbers: 72.25.Dc; 73.20.-r; 73.23.-b; 75.70.-i.

Highlights

The recent discovery of a new quantum state of matter, topological insulator, has generated a lot of interest due to its great scientific and technological importance [1,2,3,4,5]
Spin-orbit coupling opens an energy gap in the bulk, and results in helical surface states residing in the bulk gap in the absence of magnetic fields
The surface states in Bi-based alloys, Bi1xSbx, Bi2Se3, Bi2Te3, were theoretically predicted [6,8] and experimentally observed by using angle-resolved photoe-mission spectroscopy (ARPES) [9,10,11,12]. These 3D topological insulators have robust and simple surface states consisting of a single Dirac cone at the Γ point [8]

Summary

Introduction

The recent discovery of a new quantum state of matter, topological insulator, has generated a lot of interest due to its great scientific and technological importance [1,2,3,4,5]. For instance in a tunneling process, the reflected electron will reverse its spin due to the helical property of the surface states, i.e., the spin-momentum locking [14]. We investigate electron tunneling through single electric and magnetic potential barriers which can be created by depositing a ferromagnetic metallic strip on the surface of a 3D topological insulator.

Results

Conclusion