| Autor: |
Meliakov SR; P.N. Lebedev Physical Institute of the Russian Academy of Sciences, 119991 Moscow, Russia., Belykh VV; Experimentelle Physik 2, Technische Universität Dortmund, 44227 Dortmund, Germany., Kalitukha IV; Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia., Golovatenko AA; Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia., Di Giacomo A; Department of Chemistry, Ghent University, 9000 Ghent, Belgium., Moreels I; Department of Chemistry, Ghent University, 9000 Ghent, Belgium., Rodina AV; Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia., Yakovlev DR; P.N. Lebedev Physical Institute of the Russian Academy of Sciences, 119991 Moscow, Russia.; Experimentelle Physik 2, Technische Universität Dortmund, 44227 Dortmund, Germany.; Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia. |
| Abstrakt: |
Coherent spin dynamics of electrons in CdSe colloidal nanoplatelets are investigated by time-resolved pump-probe Faraday rotation at room and cryogenic temperatures. We measure electron spin precession in a magnetic field and determine g -factors of 1.83 and 1.72 at low temperatures for nanoplatelets with a thickness of 3 and 4 monolayers, respectively. The dephasing time of spin precession T2* amounts to a few nanoseconds and has a weak dependence on temperature, while the longitudinal spin relaxation time T1 exceeds 10 ns even at room temperature. Observations of single and double electron spin-flips confirm that the nanoplatelets are negatively charged. The spin-flip Raman scattering technique reveals g -factor anisotropy by up to 10% in nanoplatelets with thicknesses of 3, 4, and 5 monolayers. In the ensemble with a random orientation of nanoplatelets, our theoretical analysis shows that the measured Larmor precession frequency corresponds to the in-plane electron g -factor. We conclude that the experimentally observed electron spin dephasing and its acceleration in the magnetic field are not provided by the electron g -factor anisotropy and can be related to the localization of the resident electrons and fluctuations of the localization potential. |
