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Z(2) fractional topological insulators in two dimensions

Author(s): Repellin, C; Bernevig, Bogdan A; Regnault, N

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Abstract: We propose a simple microscopic model to numerically investigate the stability of a two-dimensional fractional topological insulator (FTI). The simplest example of an FTI consists of two decoupled copies of a Laughlin state with opposite chiralities, or double-semion phase. We focus on bosons at half filling. We study the stability of the FTI phase upon addition of two coupling terms of different nature: an interspin interaction term, and an inversionsymmetry- breaking term that couples the copies at the single-particle level. Using exact-diagonalization and entanglement spectra, we numerically show that the FTI phase is stable against both perturbations. We compare our system to a similar bilayer fractional Chern insulator. We show evidence that the time-reversal-invariant system survives the introduction of interaction coupling on a larger scale than the time-reversal-symmetry-breaking one, stressing the importance of time-reversal symmetry in the FTI phase stability. We also discuss possible fractional phases beyond nu = 1/2.
Publication Date: 1-Dec-2014
Electronic Publication Date: 1-Dec-2014
Citation: Repellin, C, Bernevig, B Andrei, Regnault, N. (2014). Z(2) fractional topological insulators in two dimensions. PHYSICAL REVIEW B, 90 (10.1103/PhysRevB.90.245401
DOI: doi:10.1103/PhysRevB.90.245401
ISSN: 1098-0121
EISSN: 1550-235X
Type of Material: Journal Article
Journal/Proceeding Title: PHYSICAL REVIEW B
Version: Final published version. Article is made available in OAR by the publisher's permission or policy.

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