Robust topological insulator conduction under strong boundary disorder

Article

关键词: SURFACE-STATES;    BI2SE3;    MODEL;   

DOI  :  10.1103/PhysRevB.88.045429

来源: SCIE

【 摘 要 】

Topological insulators are characterized by specially protected conduction on their outer boundaries. We show that the protected edge conduction exhibited by 2D topological insulators (and also Chern insulators) is independent of nonmagnetic boundary disorder. In particular, the edge states residing inside the bulk gap remain conducting even when edge-state inhomogeneities destroy the characteristic linear Dirac relation between energy and momentum. The main effects of boundary disorder on the in-gap states are to decrease the Fermi velocity, increase the density of states, pull the states into the disordered region if spin is conserved, and at very large disorder shift the states to the boundary between the disordered edge and the clean bulk. These effects, which may be useful for device engineering, are controlled by a resonance between the disordered edge and the bulk bands. The resonance's energy is set by the bulk band width; protection of the in-gap edge states' plane-wave character is controlled by the bulk band width, not the bulk band gap.

【 授权许可】

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