Overhauser effect in individual InP/GaInP dots

Sizable nuclear spin polarization is pumped in individual InP/GaInP dots in a wide range of external magnetic fields B_ext=0-5T by circularly polarized optical excitation. We observe nuclear polarization of up to ~40% at Bext=1.5T and corresponding to an Overhauser field of ~1.2T. We find a strong f...

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Bibliographic Details
Published in:arXiv.org 2008-03
Main Authors: Skiba-Szymanska, J, Nikolaenko, A V, Chekhovich, E A, Tartakovskii, A I, Makhonin, M N, Drouzas, I, Skolnick, M S, Krysa, A B
Format: Article
Language:English
Subjects:
Circular polarization
Excitons
Feedback
Magnetic fields
Nuclear spin
Optical pumping
Overhauser effect
Polarization (spin alignment)
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Summary:Sizable nuclear spin polarization is pumped in individual InP/GaInP dots in a wide range of external magnetic fields B_ext=0-5T by circularly polarized optical excitation. We observe nuclear polarization of up to ~40% at Bext=1.5T and corresponding to an Overhauser field of ~1.2T. We find a strong feedback of the nuclear spin on the spin pumping efficiency. This feedback, produced by the Overhauser field, leads to nuclear spin bi-stability at low magnetic fields of Bext=0.5-1.5T. We find that the exciton Zeeman energy increases markedly, when the Overhauser field cancels the external field. This counter-intuitive result is shown to arise from the opposite contribution of the electron and hole Zeeman splittings to the total exciton Zeeman energy.
ISSN:2331-8422
DOI:10.48550/arxiv.0710.2837