Electric field modulation of topological order in thin film semiconductors

TL;DR

This paper introduces a method to electrically modulate topological order and edge states in ultrathin semiconductor films, enabling control over their quantum properties without magnetic fields.

Contribution

It presents a novel approach using staggered periodic potentials to induce and control topological phase transitions in thin film semiconductors.

Findings

Topological phase transition achieved via electric potential.

Number of helical edge states can be step-wise tuned.

Feasibility of experimental detection discussed.

Abstract

We propose a method that can consecutively modulate the topological orders or the number of helical edge states in ultrathin film semiconductors without a magnetic field. By applying a staggered periodic potential, the system undergoes a transition from a topological trivial insulating state into a non-trivial one with helical edge states emerging in the band gap. Further study demonstrates that the number of helical edge state can be modulated by the amplitude and the geometry of the electric potential in a step-wise fashion, which is analogous to tuning the integer quantum Hall conductance by a megntic field. We address the feasibility of experimental measurement of this topological transition.