Polarization-driven topological insulator transition in a GaN/InN/GaN quantum well

TL;DR

This paper demonstrates that nanoscale engineering of GaN/InN/GaN quantum wells can induce topological insulator states by utilizing intrinsic polarization to modify energy gaps and spin-orbit interactions, even in conventional semiconductors.

Contribution

It introduces a novel approach to achieve topological insulator states in standard semiconductors through polarization-driven nanoscale engineering.

Findings

Polarization reduces energy gap and enhances spin-orbit interaction.

InN layers embedded in GaN can host topological insulator states.

The proposed structure is experimentally feasible.

Abstract

Topological insulator (TI) states have been demonstrated in materials with narrow gap and large spin-orbit interactions (SOI). Here we demonstrate that nanoscale engineering can also give rise to a TI state, even in conventional semiconductors with sizable gap and small SOI. Based on advanced first-principles calculations combined with an effective low-energy k*p Hamiltonian, we show that the intrinsic polarization of materials can be utilized to simultaneously reduce the energy gap and enhance the SOI, driving the system to a TI state. The proposed system consists of ultrathin InN layers embedded into GaN, a layer structure that is experimentally achievable.