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arXiv · 1211.1987

Disordered topological metals

Julia S. Meyer·Gil Refael
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Abstract

Topological behavior can be masked when disorder is present. A topological insulator, either intrinsic or interaction induced, may turn gapless when sufficiently disordered. Nevertheless, the metallic phase that emerges once a topological gap closes retains several topological characteristics. By considering the self-consistent disorder-averaged Green function of a topological insulator, we derive the condition for gaplessness. We show that the edge states survive in the gapless phase as edge resonances and that, similar to a doped topological insulator, the disordered topological metal also has a finite, but non-quantized topological index. We then consider the disordered Mott topological insulator. We show that within mean-field theory, the disordered Mott topological insulator admits a phase where the symmetry-breaking order parameter remains non-zero but the gap is closed, in complete analogy to 'gapless superconductivity' due to magnetic disorder.

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Julia S. Meyer, Gil Refael. 2012-11-08. Disordered topological metals. https://doi.org/10.1103/physrevb.87.104202

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