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Title
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Asymmetric versus symmetric Te double quantum wells: Bandgap tuning without electric field
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Author
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Abstract
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| We investigate the electron states in double asymmetric HgTe / Cd x Hg 1 - x Te quantum wells grown along the [ 001 ] direction. The subbands are computed by means of the envelope function approximation applied to the eight-band Kane k . mml:mspace width=".1em"mml:mspace p model. The asymmetry of the confining potential of the double quantum wells results in a gap opening, which is absent in the symmetric system where it can only be induced by an applied electric field. The bandgap and the subbands are affected by spin-orbit coupling, which is a consequence of the asymmetry of the confining potential. The electron-like and hole-like states are mainly confined in different quantum wells, and the enhanced hybridization between them opens a spin-dependent hybridization gap at a finite in-plane wavevector. We show that both the ratio of the widths of the two quantum wells and the mole fraction of the C d x H g 1 - x Te barrier control both the energy gap between the hole-like states and the hybridization gap. The energy subbands are shown to exhibit inverted ordering, and therefore, a nontrivial topological phase could emerge in the system. |
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Language
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English
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Source (journal)
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Journal of applied physics / American Institute of Physics. - New York, N.Y., 1937, currens
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Publication
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New York, N.Y.
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American Institute of Physics
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2020
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ISSN
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0021-8979
[print]
1089-7550
[online]
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DOI
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10.1063/5.0016069
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Volume/pages
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128
:6
(2020)
, p. 1-8
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Article Reference
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064301
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ISI
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000561339300001
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Medium
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E-only publicatie
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Full text (Publisher's DOI)
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Full text (publisher's version - intranet only)
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