Quantum spin hall effect in inverted type-II semiconductors

Chaoxing Liu, Taylor L. Hughes, Xiao Liang Qi, Kang Wang, Shou Cheng Zhang

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Abstract

The quantum spin Hall (QSH) state is a topologically nontrivial state of quantum matter which preserves time-reversal symmetry; it has an energy gap in the bulk, but topologically robust gapless states at the edge. Recently, this novel effect has been predicted and observed in HgTe quantum wells and in this Letter we predict a similar effect arising in Type-II semiconductor quantum wells made from InAs/GaSb/AlSb. The quantum well exhibits an "inverted" phase similar to HgTe/CdTe quantum wells, which is a QSH state when the Fermi level lies inside the gap. Due to the asymmetric structure of this quantum well, the effects of inversion symmetry breaking are essential. Remarkably, the topological quantum phase transition between the conventional insulating state and the quantum spin Hall state can be continuously tuned by the gate voltage, enabling quantitative investigation of this novel phase transition.

Original languageEnglish (US)
Article number236601
JournalPhysical Review Letters
Volume100
Issue number23
DOIs
StatePublished - Jun 11 2008

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All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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