Stability of a topological insulator:Interactions, disorder, and parity of Kramers doublets

Kagalovsky, V., Chudnovskiy, A. L. and Yurkevich, I. V. (2018). Stability of a topological insulator:Interactions, disorder, and parity of Kramers doublets. Physical Review B, 97 (24),

Abstract

We study the stability of multiple conducting edge states in a topological insulator against all multiparticle perturbations allowed by time-reversal symmetry. We model a system as a multichannel Luttinger liquid, where the number of channels equals the number of Kramers doublets at the edge. We show that in a clean system with N Kramers doublets there always exist relevant perturbations (either of a superconducting or charge density wave character) which always open N-1 gaps. In the charge density wave regime, N-1 edge states get localized. The single remaining gapless mode describes the sliding of a "Wigner-crystal"-like structure. Disorder introduces multiparticle backscattering processes. While single-particle backscattering turns out to be irrelevant, the two-particle process may localize this gapless mode. Our main result is that an interacting system with N Kramers doublets at the edge may be either a trivial insulator or a topological insulator for N=1 or 2, depending on the density-density repulsion parameters, whereas any higher number N>2 of doublets gets fully localized by disorder pinning, irrespective of the parity issue.

Publication DOI: https://doi.org/10.1103/PhysRevB.97.241116
Divisions: Engineering & Applied Sciences > Systems analytics research institute (SARI)
Engineering & Applied Sciences > Mathematics
Engineering & Applied Sciences
Additional Information: ©2018 American Physical Society
Uncontrolled Keywords: Electronic, Optical and Magnetic Materials,Condensed Matter Physics
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Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
https://journal ... sRevB.97.241116 (Publisher URL)
Published Date: 2018-06-25
Authors: Kagalovsky, V.
Chudnovskiy, A. L.
Yurkevich, I. V. ( 0000-0003-1447-8913)

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