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Optique des états collectifs et du spin
(24) Production(s) de l'année 2018
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Spin-lattice relaxation of optically polarized nuclei in p-type GaAs 
Auteur(s): Kotur M., Dzhioev R. I., Vladimirova M. , Cherbunin R. V., Sokolov P. S., Yakovlev D. R., Bayer M., Suter D., Kavokin K. V.
(Article) Publié:
Physical Review B, vol. 97 p.165206 (2018)
Texte intégral en Openaccess : 
Ref HAL: hal-01804765_v1
DOI: 10.1103/PhysRevB.97.165206
WoS: WOS:000430673700003
Exporter : BibTex | endNote
1 Citation
Résumé: Spin-lattice relaxation of the nuclear spin system in p-type GaAs is studied using a three-stage experimental protocol including optical pumping and measuring the difference of the nuclear spin polarization before and after a dark interval of variable length. This method allows us to measure the spin-lattice relaxation time T1 of optically pumped nuclei “in the dark,” that is, in the absence of illumination. The measured T1 values fall into the subsecond time range, being three orders of magnitude shorter than in earlier studied n-type GaAs. The drastic difference is further emphasized by magnetic-field and temperature dependencies of T1 in p-GaAs, showing no similarity to those in n-GaAs. This unexpected behavior finds its explanation in the spatial selectivity of the optical pumping in p-GaAs, that is only efficient in the vicinity of shallow donors, together with the quadrupole relaxation of nuclear spins, which is induced by electric fields within closely spaced donor-acceptor pairs. The developed theoretical model explains the whole set of experimental results.
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Spin temperature concept verified by optical magnetometry of nuclear spins
Auteur(s): Vladimirova M., Cronenberger S., Scalbert D., Ryzhov I. i., Zapasskii V. s., Kozlov G. g., Lemaitre A., Kavokin K. v.
(Article) Publié:
Physical Review B, vol. 97 p.041301 (2018)
Texte intégral en Openaccess : 
DOI: 10.1103/PhysRevB.97.041301
WoS: WOS:000419471200001
5 Citations
Résumé: We develop a method of nonperturbative optical control over adiabatic remagnetization of the nuclear spin system and apply it to verify the spin temperature concept in GaAs microcavities. The nuclear spin system is shown to exactly follow the predictions of the spin temperature theory, despite the quadrupole interaction that was earlier reported to disrupt nuclear spin thermalization. These findings open a way for the deep cooling of nuclear spins in semiconductor structures, with the prospect of realizing nuclear spin-ordered states for high-fidelity spin-photon interfaces.
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Complexes of dipolar excitons in layered quasi-two-dimensional nanostructures
Auteur(s): Bondarev Igor V., Vladimirova M.
(Article) Publié:
Physical Review B, vol. 97 p.165419 (2018)
Texte intégral en Openaccess :
Ref HAL: hal-01932599_v1
Ref Arxiv: 1712.10312
DOI: 10.1103/PhysRevB.97.165419
WoS: 000430058200006
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
9 Citations
Résumé: We discuss neutral and charged complexes (biexciton and trion) formed by indirect excitons in layered quasi-two-dimensional semiconductor heterostructures. Indirect excitons -- long-lived neutral Coulomb-bound pairs of electrons and holes of different layers -- have been known for semiconductor coupled quantum wells and are recently reported for van der Waals heterostructures such as bilayer graphene and transition metal dichalcogenides. Using the configuration space approach, we derive the analytical expressions for the trion and biexciton binding energies as functions of the interlayer distance. The method captures essential kinematics of complex formation to reveal significant binding energies, up to a few tens of meV for typical interlayer distances ~3-5 A, with the trion binding energy always being greater than that of the biexciton. Our results can contribute to the understanding of more complex many-body phenomena such as exciton Bose-Einstein condensation and Wigner-like electron-hole crystallization in layered semiconductor heterostructures.
Commentaires: 10 pages, 4 figures, 105 references. arXiv admin note: text overlap with arXiv:1605.02348. Réf Journal: Phys. Rev. B 97, 165419 (2018)
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