功能化 Sb(111) 单层中的量子自旋-量子反常霍尔绝缘体和拓扑相变。

Quantum Spin-Quantum Anomalous Hall Insulators and Topological Transitions in Functionalized Sb(111) Monolayers.

机构信息

†State Key Laboratory of Surface Physics and Key Laboratory for Computational Physical Sciences (MOE) and Department of Physics and ‡Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China.

出版信息

Nano Lett. 2015 Aug 12;15(8):5149-55. doi: 10.1021/acs.nanolett.5b01373. Epub 2015 Jul 16.

DOI:10.1021/acs.nanolett.5b01373

PMID:26171845

Abstract

Electronic and topological behaviors of Sb(111) monolayers decorated with H and certain magnetic atoms are investigated by using ab initio methods. The drastic exchange field induced by the magnetic atoms, together with strong spin-orbit coupling (SOC) of Sb atoms, generates one new category of valley polarized topological insulators, called quantum spin-quantum anomalous Hall (QSQAH) insulators in the monolayer, with a band gap up to 53 meV. The strong SOC is closely related to Sb px and py orbitals, instead of pz orbitals in usual two-dimensional (2D) materials. Topological transitions from quantum anomalous Hall states to QSQAH states and then to time-reversal-symmetry-broken quantum spin Hall states are achieved by tuning the SOC strength. The behind mechanism is revealed. Our work is helpful for future valleytronic and spintronic applications in 2D materials.

摘要

采用第一性原理方法研究了 H 和某些磁性原子修饰的 Sb(111)单层的电子和拓扑性质。磁性原子引起的剧烈交换场，加上 Sb 原子强烈的自旋轨道耦合（SOC），在单层中产生了一类新的谷极化拓扑绝缘体，称为量子自旋量子反常霍尔（QSQAH）绝缘体，带隙高达 53 meV。强 SOC 与 Sb px 和 py 轨道密切相关，而不是通常二维（2D）材料中的 pz 轨道。通过调节 SOC 强度，可以实现从量子反常霍尔态到 QSQAH 态，再到时间反演对称破缺量子自旋霍尔态的拓扑转变。揭示了背后的机制。我们的工作有助于二维材料中未来的谷电子学和自旋电子学应用。