Hyperfine interaction in InAs-GaAs self-assembled quantum dots : dynamical nuclear polarization versus spin relaxation - Condensed Matter > Materials ScienceReportar como inadecuado




Hyperfine interaction in InAs-GaAs self-assembled quantum dots : dynamical nuclear polarization versus spin relaxation - Condensed Matter > Materials Science - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Abstract: We report on the influence of hyperfine interaction on the opticalorientation of singly charged excitons X+ and X- in self-assembled InAs-GaAsquantum dots. All measurements were carried out on individual quantum dotsstudied by micro-photoluminescence at low temperature. We show that thehyperfine interaction leads to an effective partial spin relaxation, under50kHz modulated excitation polarization, which becomes however stronglyinhibited under steady optical pumping conditions because of dynamical nuclearpolarization. This optically created magnetic-like nuclear field can becomevery strong up to ~4 T when it is generated in the direction opposite to alongitudinally applied field, and exhibits then a bistability regime. Thiseffect is very well described by a theoretical model derived in a perturbativeapproach, which reveals the key role played by the energy cost of an electronspin flip in the total magnetic field. Eventually, we emphasize thesimilarities and differences between X+ and X- trions with respect to thehyperfine interaction, which turn out to be in perfect agreement with thetheoretical description.



Autor: O. Krebs, B. Eble, A. Lemaître, P. Voisin, B. Urbaszek, X. Marie, T. Amand

Fuente: https://arxiv.org/







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