Topological band transition between hexagonal and triangular lattices with (px, py) orbitals. (23rd June 2022)

• Record Type: Journal Article
• Authors: Hao, Xiamin; Wu, Weikang; Zhu, Jiaojiao; Song, Biyu; Meng, Qingling; Wu, Meimei; Hua, Chenqiang; Yang, Shengyuan A.; Zhou, Miao
• Is Part Of: Journal of physics. Volume 34:Number 25(2022)
• Publication Date: 2022-06-23
• Subjects: 2D structures -- multi-orbitals -- phase transition -- band structures -- topology; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/ac6473
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: By combining tight-binding modelling with density functional theory based first-principles calculations, we investigate the band evolution of two-dimensional (2D) hexagonal lattices with ( p x, p y ) orbitals, focusing on the electronic structures and topological phase transitions. The ( p x, p y )-orbital hexagonal lattice model possesses two flat bands encompassing two linearly dispersive Dirac bands. Breaking the A/B sublattice symmetry could transform the model into two triangular lattices, each featuring a flat band and a dispersive band. Inclusion of the spin–orbit coupling and magnetization may give rise to quantum spin Hall and quantum anomalous Hall (QAH) states. As a proof of concept, we demonstrate that half-hydrogenated stanene is encoded by a triangular lattice with ( p x, p y ) orbitals, which exhibits ferromagnetism and QAH effect with a topological gap of ∼0.15 eV, feasible for experimental observation. These results provide insights into the structure-property relationships involving the orbital degree of freedom, which may shed light on future design and preparation of 2D topological materials for novel electronic/spintronic and quantum computing devices.