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Title
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Excitonic Aharonov-Bohm effect : unstrained versus strained type-I semiconductor nanorings
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Author
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Abstract
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| We study how mechanical strain affects the magnetic field dependence of the exciton states in type-I semiconductor nanorings. Strain spatially separates the electron and hole in (In,Ga)As/GaAs nanorings which is beneficial for the occurrence of the excitonic Aharonov-Bohm (AB) effect. In narrow strained (In,Ga)As/GaAs nanorings the AB oscillations in the exciton ground-state energy are due to anticrossings with the first excited state. No such AB oscillations are found in unstrained GaAs/(Al,Ga)As nanorings irrespective of the ring width. Our results are obtained within an exact numerical diagonalization scheme and are shown to be accurately described by a two-level model with off-diagonal coupling t. The later transfer integral expresses the Coulomb coupling between states of electron-hole pairs. We also found that the oscillator strength for exciton recombination in (In,Ga)As/GaAs nanorings exhibits AB oscillations, which are superimposed on a linear increase with magnetic field. Our results agree qualitatively with recent experiments on the excitonic Aharonov-Bohm effect in type-I (In,Ga)As/GaAs nanorings. |
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Language
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English
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Source (journal)
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Physical review : B : condensed matter and materials physics. - Lancaster, Pa, 1998 - 2015
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Publication
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Lancaster, Pa
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2011
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ISSN
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1098-0121
[print]
1550-235X
[online]
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DOI
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10.1103/PHYSREVB.84.125307
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Volume/pages
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84
:12
(2011)
, p. 125307,1-125307,13
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Article Reference
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125307
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ISI
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000294777400013
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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 (open access)
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