Spontaneous Spin Coherence in n-GaAs Produced by Ferromagnetic Proximity Polarization

We find that photoexcited electrons in an n-GaAs epilayer rapidly (< 50 ps) spin-polarize due to the proximity of an epitaxial ferromagnetic metal. Comparison between MnAs/GaAs and Fe/GaAs structures reveals that this coherent spin polarization is aligned antiparallel and parallel to their magnet...

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Bibliographic Details
Main Authors Epstein, R. J, Malajovich, I, Kawakami, R. K, Chye, Y, Hanson, M, Petroff, P. M, Gossard, A. C, Awschalom, D. D
Format Journal Article
LanguageEnglish
Published 18.01.2002
Subjects
Physics - Materials Science
Physics - Mesoscale and Nanoscale Physics
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Summary:We find that photoexcited electrons in an n-GaAs epilayer rapidly (< 50 ps) spin-polarize due to the proximity of an epitaxial ferromagnetic metal. Comparison between MnAs/GaAs and Fe/GaAs structures reveals that this coherent spin polarization is aligned antiparallel and parallel to their magnetizations, respectively. In addition, the GaAs nuclear spins are dynamically polarized with a sign determined by the spontaneous electron spin orientation. In Fe/GaAs, competition between nuclear hyperfine and applied magnetic fields results in complete quenching of electron spin precession.
DOI:10.48550/arxiv.cond-mat/0201350