Materials Research Laboratory and Materials Department, University of California, Santa Barbara, California 93106-5050, USA.
Phys Rev Lett. 2012 Nov 2;109(18):186803. doi: 10.1103/PhysRevLett.109.186803.
Topological insulator (TI) states have been demonstrated in materials with a 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 a 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.
拓扑绝缘体 (TI) 态已在具有窄能隙和大自旋轨道相互作用 (SOI) 的材料中得到证实。在这里，我们证明即使在具有较大能隙和较小 SOI 的常规半导体中，纳米级工程也可以产生 TI 态。基于先进的第一性原理计算和有效的低能 k·p 哈密顿量，我们表明材料的固有极化可以被用来同时减小能隙并增强 SOI，从而使系统进入 TI 态。所提出的系统由嵌入 GaN 中的超薄 InN 层组成，这是一种实验上可实现的层状结构。
