Fractional charged edge states in ladder topological insulators
We propose a model of two-leg ladder topological insulator in which the spin-orbit couplings are presented in both intra-chain and inter-chain interactions. The topological phase supports four fractional charged edge states localized at opposite ends of the ladder, which belongs to the chiral symple...
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Published in | Journal of physics. Condensed matter Vol. 31; no. 12; p. 125402 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
England
IOP Publishing
27.03.2019
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Subjects | |
Online Access | Get full text |
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Summary: | We propose a model of two-leg ladder topological insulator in which the spin-orbit couplings are presented in both intra-chain and inter-chain interactions. The topological phase supports four fractional charged edge states localized at opposite ends of the ladder, which belongs to the chiral symplectic (CII) class protected by time-reversal symmetry and chiral symmetry. In our model, the presence of time-reversal and chiral symmetry generates fourfold degeneracy for the edge states, and the two edge states with same chirality at one end of the ladder each carries half charge. In contrast to the two edge states spatially localized at one end of the ladder being not distinguished, these two edge states can be detected by the momentum density. The experimental scheme for realizing our model with cold atoms in optical lattice is discussed. By introducing a magnetic field in the x direction, the system is driven from CII class to AIII class. In AIII class, there exist two distinct topological phases that exhibit four degenerate edge states and two degenerate edge states in the gap, respectively. As same as the system in CII class, each edge state carries a half charge in AIII class. |
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Bibliography: | JPCM-112745.R2 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0953-8984 1361-648X |
DOI: | 10.1088/1361-648X/aaff16 |