Abstract
Disorder plays an important role in two dimensions, and is responsible for striking phenomena such as metal-insulator transition and the integral and fractional quantum Hall effects. In this Letter, we investigate the role of disorder in the context of the recently discovered topological insulator, which possesses a pair of helical edge states with opposing spins moving in opposite directions and exhibits the phenomenon of quantum spin Hall effect. We predict an unexpected and nontrivial quantum phase termed “topological Anderson insulator,” which is obtained by introducing impurities in a two-dimensional metal; here disorder not only causes metal-insulator transition, as anticipated, but is fundamentally responsible for creating extended edge states. We determine the phase diagram of the topological Anderson insulator and outline its experimental consequences.
- Received 18 November 2008
DOI:https://doi.org/10.1103/PhysRevLett.102.136806
©2009 American Physical Society
Synopsis
Dirt and geometry insulate electrons
Published 6 April 2009
Random disorder in topological insulators leads to an insulating phase reminiscent of one known for years in two-dimensional systems.
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