Browsing by Author "Climente, Juan I."

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Dominant channels of exciton spin relaxation in photoexcited self-assembled (In,Ga)As quantum dots
(2011-04-22)
Liao, Yu-Huai
;
Climente, Juan I.
;
Cheng, Shun-Jen
;
電子物理學系
;
Department of Electrophysics
We present a comprehensive theoretical investigation of spin relaxation processes of excitons in photoexcited self-assembled quantum dots. The exciton spin relaxations are considered between dark- and bright-exciton states via the channels created by various spin-admixture mechanisms, including electron Rashba and Dresselhaus spin-orbital couplings (SOCs), hole linear and hole cubic SOCs, and electron hyperfine interactions, incorporated with single-and double-phonon processes. The hole-Dresselhaus SOC is identified as the dominant spin-admixture mechanism, leading to relaxation rates as fast as similar to 10(-2) ns(-1), consistent with recent observations. Moreover, due to significant electron-hole exchange interactions, single-phonon processes are unusually dominant over two-phonon ones in a photoexcited dot even at temperatures as high as 15K.