Light-hole exciton spin relaxation in quantum dots
| Autor: | E. Tsitsishvili |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
Physics
Valence (chemistry) Exciton Exchange interaction Astrophysics::Cosmology and Extragalactic Astrophysics Condensed Matter::Mesoscopic Systems and Quantum Hall Effect Condensed Matter Physics Thermal conduction Electronic Optical and Magnetic Materials Condensed Matter::Materials Science Dark state Quantum dot Atomic physics Order of magnitude Biexciton |
| Zdroj: | Physical Review B. 91 |
| ISSN: | 1550-235X 1098-0121 |
| DOI: | 10.1103/physrevb.91.155434 |
| Popis: | The phonon-induced flip of the exciton spin in single flat semiconductor quantum dots with a light-hole exciton ground state is studied. The corresponding quartet, split by the exchange interaction, consists of three bright states and a dark state located energetically below the bright exciton. The two in-plane polarized bright states contribute to single-phonon transitions to the dark state and also to the upper bright state polarized in the $z$ growth direction of the dot. For these processes, the presented analytical results are calculated for the relaxation driven by the spin-orbit interaction in the conduction and the light-hole valence subbands. The estimated spin-relaxation times at low temperature are (at least) one order of magnitude lower than the bright exciton lifetime. Two other possible transitions, within the in-plane polarized doublet and between the $z$-polarized bright and dark states as well, proceed via intermediate states with a contribution from two acoustic phonons. These processes are strongly suppressed at low temperature, whereas they appear to be of the same intensity as single-phonon transitions at high enough temperatures. |
| Databáze: | OpenAIRE |
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