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arXiv 1306.2520cond-mat.mes-hall
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拓扑绝缘体、自旋和紧束缚方法

Topological insulators, spin, and the tight-binding method

Warren J. Elder, Eng Soon Tok, Dimitri D. Vvedensky, Jing Zhang

摘要:

作为最早提出的拓扑保护态之一,石墨烯中的量子自旋霍尔效应关键地依赖于布里渊区的K/K'点处的自旋相关能隙的存在。使用紧束缚的不变量的方法的基础上制定的,我们确定了这样一个内在的差距的起源由自旋轨道相互作用所造成的π轨道之间的三个中心的相互作用。这种方法结合了所有的对称性兼容的相互作用,以前被忽视,并有更广泛的应用第一性原理计算和紧束缚方法之间的比较。它还确定了一个修正Halfton模型及其推广,其中纳入了自旋自由度,并再现了石墨烯中量子自旋霍尔效应所需的所有显着特征。

英文摘要:

As one of the first proposed topologically protected states, the quantum spin Hall effect in graphene relies critically on the existence of a spin-dependent gap at the K/K' points of the Brillouin zone. Using a tight-binding formulation based on the method of invariants, we identify the origin of such an intrinsic gap as the three-center interaction between the pi-orbitals caused by spin-orbit interactions. This methodology incorporates all symmetry compliant interactions previously neglected and has wider applications for comparisons between first-principle calculations and the tight-binding method. It also identifies a correction to the Haldane model and its generalization, which incorporates the spin degrees of freedom and reproduces all the salient features required for the quantum spin Hall effect in graphene.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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