Electron Spin Coherence in CdSe Nanocrystals in a Glass Matrix.

Autor: Qiang G; Experimentelle Physik 2, Technische Universität Dortmund, 44221Dortmund, Germany., Zhukov EA; Ioffe Institute, Russian Academy of Sciences, 194021St. Petersburg, Russia., Evers E; Experimentelle Physik 2, Technische Universität Dortmund, 44221Dortmund, Germany., Yakovlev DR; Experimentelle Physik 2, Technische Universität Dortmund, 44221Dortmund, Germany.; Ioffe Institute, Russian Academy of Sciences, 194021St. Petersburg, Russia., Golovatenko AA; Ioffe Institute, Russian Academy of Sciences, 194021St. Petersburg, Russia., Rodina AV; Ioffe Institute, Russian Academy of Sciences, 194021St. Petersburg, Russia., Onushchenko AA; ITMO University, 199053St. Petersburg, Russia., Bayer M; Experimentelle Physik 2, Technische Universität Dortmund, 44221Dortmund, Germany.; Ioffe Institute, Russian Academy of Sciences, 194021St. Petersburg, Russia.
Jazyk: angličtina
Zdroj: ACS nano [ACS Nano] 2022 Nov 22; Vol. 16 (11), pp. 18838-18848. Date of Electronic Publication: 2022 Nov 01.
DOI: 10.1021/acsnano.2c07645
Abstrakt: The coherent spin dynamics of electrons in CdSe nanocrystals embedded in a glass matrix with diameters from 3.3 up to 6.1 nm are investigated by time-resolved Faraday ellipticity at room and cryogenic temperatures. Only one Larmor precession frequency is detected, which corresponds to the larger of the two precession frequencies and thus g -factor values found in the typical signal from solution-grown colloidal CdSe nanocrystals. We identify this frequency accordingly as associated with the spin precession of resident electrons localized in the nanocrystals in the vicinity of the surface. We provide a detailed theoretical analysis of the exciton level spin structure in the magnetic field and model the spin dynamics in CdSe nanocrystals of different symmetries. This allows us to exclude the exciton as the origin of the experimentally observed oscillating signal. At a cryogenic temperature of 6 K, an additional nonoscillating component emerges in the spin dynamics. We consider several possible origins of this signal and conclude that it is related to the hole spin polarization.
Databáze: MEDLINE
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