Current-Induced Gap Opening in Interacting Topological Insulator Surfaces
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Current-Induced Gap Opening in Interacting Topological Insulator Surfaces. / Balram, Ajit C.; Flensberg, Karsten; Paaske, Jens; Rudner, Mark S.
I: Physical Review Letters, Bind 123, Nr. 24, 246803, 11.12.2019.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Current-Induced Gap Opening in Interacting Topological Insulator Surfaces
AU - Balram, Ajit C.
AU - Flensberg, Karsten
AU - Paaske, Jens
AU - Rudner, Mark S.
N1 - [Qdev]
PY - 2019/12/11
Y1 - 2019/12/11
N2 - 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.
AB - 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.
U2 - 10.1103/PhysRevLett.123.246803
DO - 10.1103/PhysRevLett.123.246803
M3 - Journal article
C2 - 31922820
AN - SCOPUS:85076507843
VL - 123
JO - Physical Review Letters
JF - Physical Review Letters
SN - 0031-9007
IS - 24
M1 - 246803
ER -
ID: 232491532