Fingerprint of different spin-orbit terms for spin transport in HgTe quantum wells

D. G. Rothe, R. W. Reinthaler, C. X. Liu, L. W. Molenkamp, S. C. Zhang, E. M. Hankiewicz

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128 Scopus citations

Abstract

Using k · p theory, we derive an effective four-band model describing the physics of the typical two-dimensional topological insulator (HgTe/CdTe quantum well (QW)) in the presence of an out-of-plane (in the z-direction) inversion breaking potential and an in-plane potential. We find that up to third order in perturbation theory, only the inversion breaking potential generates new elements to the four-band Hamiltonian that are off-diagonal in spin space. When this new effective Hamiltonian is folded into an effective twoband model for the conduction (electron) or valence (heavy hole) bands, two competing terms appear: (i) a Rashba spin-orbit interaction originating from inversion breaking potential in the z-direction and (ii) an in-plane Pauli term as a consequence of the in-plane potential. Spin transport in the conduction band is further analysed within the Landauer-Büttiker formalism. We find that for asymmetrically doped HgTe QWs, the behaviour of the spin-Hall conductance is dominated by the Rashba term.

Original languageEnglish (US)
Article number065012
JournalNew Journal of Physics
Volume12
DOIs
StatePublished - Jun 17 2010

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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