Teshome Tamiru, Datta Ayan
School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A and 2B Raja S. C. Mullick Road, Jadavpur, Kolkata, 700032 West Bengal, India.
ACS Omega. 2019 May 17;4(5):8701-8706. doi: 10.1021/acsomega.9b00613. eCollection 2019 May 31.
Topological insulating materials with dissipationless surface states promise potential applications in spintronic materials. Through density functional theory, we proposed a new class of topological phase transition in SbMg on the basis of tensile strain. At the equilibrium state, SbMg corresponds to a normal insulator, and under the influence of tensile strain, the band gaps are gradually tuned. At ε = 7.2%, the nontrivial phase is achieved due to spin-orbital coupling (SOC), and a nontrivial topological phase band gap of 0.22 eV is opened. As a result, the Dirac cone is locked in the bulk, which is associated to p band crossing. Interestingly, the tuning of nontrivial topological properties with tensile strain leading to spin saturation indicates an orbital-filtering effect. The surface state of the SbMg material is determined by the topological invariant, = 1, at the critical tensile strain in the presence of the SOC effect. This study enhances the scope of topological insulators and current platforms to design new spintronic devices.
具有无耗散表面态的拓扑绝缘材料有望在自旋电子材料中得到潜在应用。通过密度泛函理论，我们基于拉伸应变提出了SbMg中的一类新型拓扑相变。在平衡态下，SbMg对应于正常绝缘体，在拉伸应变的影响下，带隙逐渐被调节。在ε = 7.2%时，由于自旋轨道耦合（SOC）实现了非平凡相，并打开了0.22 eV的非平凡拓扑相带隙。结果，狄拉克锥被锁定在体相中，这与p带交叉相关。有趣的是，通过拉伸应变调节非平凡拓扑性质导致自旋饱和表明了一种轨道过滤效应。在存在SOC效应的临界拉伸应变下，SbMg材料的表面态由拓扑不变量 = 1决定。这项研究扩展了拓扑绝缘体和当前设计新自旋电子器件平台的范围。
