Current-Induced Gap Opening in Interacting Topological Insulator Surfaces
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Dokumenter
- PhysRevLett.123.246803
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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.
Originalsprog | Engelsk |
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Artikelnummer | 246803 |
Tidsskrift | Physical Review Letters |
Vol/bind | 123 |
Udgave nummer | 24 |
Antal sider | 6 |
ISSN | 0031-9007 |
DOI | |
Status | Udgivet - 11 dec. 2019 |
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