Electric control of the bandgap in quantum wells with band-inverted junctions

TL;DR

This paper demonstrates that applying an electric field to band-inverted quantum wells can dynamically control and reduce the interface energy gap, enabling tunable electronic properties in semiconductor heterostructures.

Contribution

It introduces a method to electrically tune the interface gap in band-inverted quantum wells, expanding the potential for device applications.

Findings

Electric field reduces the interface gap in quantum wells.

The interface dispersion is quadratic in momentum.

Electric control enables dynamic tuning of the bandgap.

Abstract

In IV-VI semiconductor heterojunctions with band-inversion, such as those made of Pb$_{1-x}$Sn$_{x}$Te or Pb$_{1-x}$Sn$_{x}$Se, interface states are properly described by a two-band model, predicting the appearance of a Dirac cone in single junctions. However, in quantum wells the interface dispersion is quadratic in momentum and the energy spectrum presents a gap. We show that the interface gap shrinks under an electric field parallel to the growth direction. Therefore, the interface gap can be dynamically tuned in experiments on double-gated quantum wells based on band-inverted compounds.