Effective Model for Massless Dirac Electrons on a Surface of Weak Topological Insulators

被引:9
作者
Arita, Takashi [1 ]
Takane, Yositake [1 ]
机构
[1] Hiroshima Univ, Grad Sch Adv Sci Matter, Dept Quantum Matter, Hiroshima 7398530, Japan
关键词
D O I
10.7566/JPSJ.83.124716
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
In a typical situation, gapless surface states of a three-dimensional (3D) weak topological insulator (WTI) appear only on the sides, leaving the top and bottom surfaces gapped. To describe massless Dirac electrons emergent on such side surfaces of a WTI, a two-dimensional (2D) model consisting of a series of one-dimensional helical channels is usually employed. However, an explicit derivation of such a model from a 3D bulk Hamiltonian has been lacking. Here, we explicitly derive an effective 2D model for the WTI surface states starting from the Wilson-Dirac Hamiltonian for the bulk WTI and establish a firm basis for the hitherto hypothesized 2D model. We show that the resulting 2D model accurately reproduces the excitation spectrum of surface Dirac electrons determined by the 3D model. We also show that the 2D model is applicable to a side surface with atomic steps.
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页数:7
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