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Spin relaxation of positive trions in InAs/GaAs quantum dots: the role of hyperfine interaction
Author(s) -
Braun PierreFrançois,
Eble Benoît,
Lombez Laurent,
Urbaszek Bernhard,
Marie Xavier,
Amand Thierry,
Renucci Pierre,
Krebs Olivier,
Lemaître Aristide,
Voisin Paul,
Kalevich Vladimir K.,
Kavokin Kyrill V.
Publication year - 2006
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200671528
Subject(s) - trion , hyperfine structure , condensed matter physics , photoluminescence , quantum dot , dephasing , spins , relaxation (psychology) , spin polarization , electron , excited state , polarization (electrochemistry) , magnetic field , physics , atomic physics , chemistry , exciton , optoelectronics , quantum mechanics , psychology , social psychology
We report on positive trion (X + ) spin relaxation in self‐assembled InAs/GaAs quantum dots. The hyperfine interaction between the electron and nuclear spins acts as a randomly oriented magnetic field for the electron spin, giving rise to ensemble dephasing and thus to partial relaxation in less than 1 ns. Time‐resolved photoluminescence polarization measurements carried out on an ensemble of InAs/GaAs quantum dots, charged with excess holes by proximity p‐doping, reveal this peculiar dynamics. The fast polarization decrease can be efficiently suppressed by screening the hyperfine interaction with a longitudinal magnetic field of 100 mT. The quenching of this hyperfine‐induced relaxation is also evidenced for a single charge‐tunable quantum dot in the regime of X + photoluminescence and excited with modulated polarization to prevent dynamic nuclear polarization. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)