Current-induced gap opening in interacting topological insulator surfaces

Abstract

Two-dimensional topological insulators (TIs) host gapless helical edge states that are predicted to support a quantized two-terminal conductance. Quantization is protected by time-reversal symmetry, which forbids elastic backscattering. Paradoxically, the current-carrying state itself breaks the time-reversal symmetry that protects it. Here we show that the combination of electron-electron interactions and momentum-dependent spin polarization in helical edge states gives rise to feedback through which an applied current opens a gap in the edge state dispersion, thereby breaking the protection against elastic backscattering. Current-induced gap opening is manifested via a nonlinear contribution to the system's $I-V$ characteristic, which persists down to zero temperature. We discuss prospects for realizations in recently discovered large bulk band gap TIs, and an analogous current-induced gap opening mechanism for the surface states of three-dimensional TIs.

6 pages, 2 figures, published version

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Cited by in corpus (13)

• Non-linear Hall Effects: Mechanisms and Materials
• Helical Liquids in Semiconductors
• Determination of the spin axis in quantum spin Hall insulator monolayer WTe2
• Accessing the spectral function in a current-carrying device
• Anomalous localization at the boundary of an interacting topological insulator
• Cooperative orbital moments and edge magnetoresistance in monolayer WTe${}_2$
• Elastic backscattering of quantum spin Hall edge modes from Coulomb interactions with non-magnetic impurities
• Robustness of Helical Edge States Under Edge Reconstruction
• Momentum relaxation effects in 2D-Xene field effect device structures
• Interaction- and phonon-induced topological phase transitions in double helical liquids
• Dynamic impurities in two-dimensional topological insulator-edge states
• Energy magnetization and transport in systems with a non-zero Berry curvature in a magnetic field
• Edge Reconstruction in a Quantum Spin Hall Insulator