Finite size effects on the quantum spin Hall state

We theoretically study the helical edge states in the quantum spin Hall (QSH) effect based on an effective 4-band tight-binding model for HgTe/CdTe quantum wells. We microscopically describe the spatial dependence of the helical edge modes in the QSH state. It is found that the helical edge states a...

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Bibliographic Details
Published inJournal of physics. Conference series Vol. 266; no. 1; pp. 012103 - 4
Main Authors Ohyama, Yuichi, Tsuchiura, Hiroki, Sakuma, Akimasa
Format Journal Article
LanguageEnglish
Published Bristol IOP Publishing 01.01.2011
Subjects
Boundaries
Cadmium tellurides
Channels
Helical
Mathematical analysis
Mathematical models
Physics
Quantum wells
Scattering
Size effects
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Summary:We theoretically study the helical edge states in the quantum spin Hall (QSH) effect based on an effective 4-band tight-binding model for HgTe/CdTe quantum wells. We microscopically describe the spatial dependence of the helical edge modes in the QSH state. It is found that the helical edge states are gapped when the width of sample narrows. This is because the edge states on the opposite boundary of the sample overlap each other, and then the backward scattering channel opens up.
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ISSN:1742-6596
1742-6588
1742-6596
DOI:10.1088/1742-6596/266/1/012103