Gate-voltage-induced switching of the Rashba spin-orbit interaction in a composition-adjusted quantum well

The coefficient α of the Rashba spin-orbit interaction is calculated in an asymmetric quantum well consisting of Ga0.47In0.53As (well), Al0.48In0.52As (left barrier), and AlxGa1−xAsySb1−y (right barrier) as a function of the external electric field perpendicular to the well Ezex which is controlled...

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Bibliographic Details
Published in:Physical review. B 2017-01, Vol.95 (4), Article 045301
Main Authors: Akera, Hiroshi, Suzuura, Hidekatsu, Egami, Yoshiyuki
Format: Article
Language:English
Subjects:
Barrier layers
Composition
Electric fields
Electric potential
Mathematical analysis
Polarity
Quantum wells
Spin-orbit interactions
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Summary:The coefficient α of the Rashba spin-orbit interaction is calculated in an asymmetric quantum well consisting of Ga0.47In0.53As (well), Al0.48In0.52As (left barrier), and AlxGa1−xAsySb1−y (right barrier) as a function of the external electric field perpendicular to the well Ezex which is controlled by the gate voltage. This coefficient α, which depends on the band offset, can be tuned to be zero by adjusting the Al fraction x in the right barrier layer to the optimum value x0 in the case where the wave function vanishes at the left heterointerface. Such a composition-adjusted asymmetric quantum well is proposed as a structure in which the magnitude of α can be switched by changing the polarity of Ezex. The calculation shows that, when |x−x0|40 for a large enough |Ezex| (|Ezex|>107 V/m for a well width of 20 nm), which results in the on/off spin-relaxation-rate ratio exceeding 103 in the Dyakonov-Perel mechanism.
ISSN:2469-9950
2469-9969
DOI:10.1103/PhysRevB.95.045301