The fate of topological-insulator surface states under strong disorder

Abstract

Three-dimensional topological insulators feature Dirac-like surface states which are topologically protected against the influence of weak quenched disorder. Here we investigate the effect of surface disorder beyond the weak-disorder limit using large-scale numerical simulations. We find two qualitatively distinct regimes: Moderate disorder destroys the Dirac cone and induces diffusive metallic behavior at the surface. Even more remarkably, for strong surface disorder a Dirac cone reappears, as new weakly disordered "surface" states emerge in the sample beneath the disordered surface layer, which can be understood in terms of an interface between a topological and an Anderson insulator. Together, this demonstrates the drastic effect of disorder on topological surface states, which cannot be captured within effective two-dimensional models for the surface states alone.

4.3 pages, 4 figs

References in corpus (6)

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• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Three dimensional topological invariants for time reversal invariant Hamiltonians and the three dimensional quantum spin Hall effect
• Topological delocalization of two-dimensional massless Dirac fermions
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Cited by in corpus (7)

• Topological surface states in nodal superconductors
• Topological protection, disorder, and interactions: Survival at the surface of 3D topological superconductors
• Modification and Control of Topological Insulator Surface States Using Surface Disorder
• Response of the topological surface state to surface disorder in TlBiSe${}_2$
• Kondo holes in topological Kondo insulators: Spectral properties and surface quasiparticle interference
• Helical Majorana surface states of strongly disordered topological superconductors with time-reversal symmetry
• Strong correlations at topological insulator surfaces and the breakdown of the bulk-boundary correspondence