Electric control of topological phase transitions in Dirac semimetal thin films

TL;DR

This paper demonstrates how applying a vertical electric field to Dirac semimetal thin films can induce topological phase transitions, enabling electrical control of topological edge states for potential transistor applications.

Contribution

It reveals the mechanism of electric-field-induced topological phase transitions in Dirac semimetal thin films, combining quantum confinement and sub-band coupling effects.

Findings

Electric field can invert sub-band gaps in Dirac semimetal thin films.

Topological phase transition from trivial insulator to quantum spin Hall insulator.

Electrical switching of topological edge channels demonstrated.

Abstract

We investigate the effect of a vertical electric field on a Dirac semimetal thin film. We show that through the interplay between the quantum confinement effect and the field-induced coupling between sub-bands, the sub-band gap can be tuned and inverted, during which the system undergoes a topological phase transition between a trivial band insulator and a quantum spin Hall insulator. Consequently, one can electrically switch the topological edge channels on and off, making the system a promising platform for constructing a topological field effect transistor.