Gapless Interface States between Topological Insulators with Opposite Dirac Velocities

被引：96

作者：

Takahashi, Ryuji ^{[1
]}

Murakami, Shuichi ^{[1
,2
]}

机构：

[1] Tokyo Inst Technol, Dept Phys, Meguro Ku, Tokyo 1528551, Japan

[2] Japan Sci & Technol Agcy JST, PRESTO, Kawaguchi, Saitama 3320012, Japan

来源：

PHYSICAL REVIEW LETTERS | 2011年 / 107卷 / 16期

关键词：

HALL CONDUCTANCE; GRAPHENE; LENS;

D O I：

10.1103/PhysRevLett.107.166805

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

The Dirac cone on a surface of a topological insulator shows linear dispersion analogous to optics and its velocity depends on materials. We consider a junction of two topological insulators with different velocities, and calculate the reflectance and transmittance. We find that they reflect the backscattering-free nature of the helical surface states. When the two velocities have opposite signs, both transmission and reflection are prohibited for normal incidence, when a mirror symmetry normal to the junction is preserved. In this case we show that there necessarily exist gapless states at the interface between the two topological insulators. Their existence is protected by mirror symmetry, and they have characteristic dispersions depending on the symmetry of the system.

引用

页数：4

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