Surface Step Defect in 3D Topological Insulators: Electric Manipulation of Spin and Quantum Spin Hall Effect

Abstract

We study the influence of step defect on surface states in three-dimensional topological insulators subject to a perpendicular magnetic field. By calculating the energy spectrum of the surface states, we find that Landau levels (LLs) can form on flat regions of the surface and are distant from the step defect, and several subbands emerge at side surface of the step defect. The subband which connects to the two zeroth LLs is spin-polarized and chiral. In particular, when the electron transports along the side surface, the electron spin direction can be manipulated arbitrarily by gate voltage. And no reflection occurs even if the electron spin direction is changed. This provides a fascinating avenue to control the electron spin easily and coherently. In addition, regarding the subbands with high LL index, there exist spin-momentum locking helical states and the quantum spin Hall effect can appear.

6 pages, 5 figures

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Cited by in corpus (4)

• Exact edge, bulk and bound states of finite topological systems
• Connection topology of step edge state bands at the surface of a three dimensional topological insulator
• Quantum transport through three-dimensional topological insulator p-n junction under magnetic field
• Bound states and controllable currents on Topological Insulator surfaces with extended magnetic defects