Polarization-driven topological insulator transition in a GaN/InN/GaN quantum well
M. S. Miao, Q. Yan, C. G. Van de Walle, W. K. Lou, L. L. Li, K. Chang
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.