Spontaneous gap generation on the surface of weakly interacting topological insulators using nonmagnetic impurities

Abstract

Strong nonmagnetic impurities on the surface of three-dimensional topological insulators (TIs) generate localized resonance peaks close to the Dirac point. We show that this results in a strongly reduced critical Coulomb interaction strength to reach a magnetic surface state, following a Stoner-like criterion. Thus even weakly interacting TIs host a finite (local) magnetization around strong nonmagnetic impurities. The local magnetization gives rise to a global energy gap, linearly dependent on the maximum value of the magnetization but decreasing with reduced impurity concentration.

4.5 pages + 1 page supplementary material, 3 figures

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Cited by in corpus (3)

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• Spectromicroscopic measurement of surface and bulk band structure interplay in a disordered topological insulator