Robust topological insulator surface conduction under strong surface disorder

Abstract

Topological insulators are characterized by specially protected conduction on their outer boundaries. We show that the protected edge conduction exhibited by 2-D topological insulators (and also Chern insulators) is independent of non-magnetic 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.

References in corpus (17)

• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Gate-Voltage Control of Chemical Potential and Weak Anti-localization in Bismuth Selenide
• Topological Anderson Insulator
• Bulk Fermi surface coexistence with Dirac surface state in Bi${}_2$Se${}_3$: a comparison of photoemission and Shubnikov-de Haas measurements
• Rapid Surface Oxidation as a Source of Surface Degradation Factor for Bi2Se3
• Single valley Dirac fermions in zero-gap HgTe quantum wells
• Topological delocalization of two-dimensional massless Dirac fermions
• Transport in three-dimensional topological insulators: theory and experiment
• Two-dimensional spin-filtered chiral network model for the Z_2 quantum spin-Hall effect
• Surface versus bulk state in topological insulator Bi2Se3 under environmental disorder
• The fate of topological-insulator surface states under strong disorder
• Three-dimensional phase diagram of disordered HgTe/CdTe Quantum spin-Hall wells
• Localization and Mobility Gap in Topological Anderson Insulator
• Effects of Smooth Boundaries on Topological Edge Modes in Optical Lattices
• Disorder-Induced Multiple Transition involving Z2 Topological Insulator
• Phase Structure of the Topological Anderson Insulator
• Coherent Oscillations and Giant Edge Magnetoresistance in Singly Connected Topological Insulators

Cited by in corpus (8)

• Density of States Scaling at the Semimetal to Metal Transition in Three Dimensional Topological Insulators
• Stretched exponential decay of Majorana edge modes in many-body localized Kitaev chains under dissipation
• Modification and Control of Topological Insulator Surface States Using Surface Disorder
• Quantum Valley Hall effect without Berry curvature
• Floquet topological transitions in extended Kane-Mele models with disorder
• Bulk effects on topological conduction on the surface of 3-D topological insulators
• Topological state transfers in cavity-magnon system
• Effect of surface disorder on the chiral surface states of a three-dimensional quantum Hall system