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- Chen, Shula, 1986-, et al.
(author)
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Power-dependent spin amplification in (In, Ga)As/GaAs quantum well via Pauli blocking by tunnel-coupled quantum dot ensembles
- 2016
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In: Applied Physics Letters. - Melville, NY, United States : A I P Publishing LLC. - 0003-6951 .- 1077-3118. ; 108:15
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Journal article (peer-reviewed)abstract
- Power-dependent time-resolved optical spin orientation measurements were performed on In0.1Ga0.9As quantum well(QW) and In0.5Ga0.5As quantum dot (QD) tunnel-coupled structures with an 8-nm-thick GaAs barrier. A fast transient increase of electron spin polarization was observed at the QW ground state after circular-polarized pulse excitation. The temporal maximum of polarization increased with increasing pumping fluence owing to enhanced spin blocking in the QDs, yielding a highest amplification of 174% with respect to the initial spin polarization. Further elevation of the laser power gradually quenched the polarizationdynamics, which was induced by saturated spin filling of both the QDs and the QW phase spaces.
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| 2. |
- Chen, Shula, 1986-, et al.
(author)
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Temperature-dependent spin injection dynamics in InGaAs/GaAs quantum well-dot tunnel-coupled nanostructures
- 2016
-
In: Applied Physics Letters. - Melville, NY, United States : A I P Publishing LLC. - 0003-6951 .- 1077-3118. ; 119
-
Journal article (peer-reviewed)abstract
- Time-resolved optical spin orientation spectroscopy was employed to investigate the temperature-dependent electron spin injection in In0.1Ga0.9As quantum well (QW) and In0.5Ga0.5As quantum dots (QDs) tunnel-coupled nanostructures with 4, 6, and 8 nm-thick GaAs barriers. The fast picosecond-ranged spin injection from QW to QDexcited states (ES) was observed to speed up with temperature, as induced by pronounced longitudinal-optical (LO)-phonon-involved multiple scattering process, which contributes to a thermally stable and almost fully spin-conserving injection within 5–180 K. The LO-phonon coupling was also found to cause accelerated electron spin relaxation of QD ES at elevated temperature, mainly via hyperfine interaction with random nuclear field.
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