Date : 19/05/2011 à 14:30
Titre : Electron spin decoherence in nanostructures
Intervenant : Zhenia Ivchenko
Provenance : Institut A. F. Ioffe, St Petersbourg
Salle : Seminaire (2ieme etage)
Résumé : I will present a theory of spin Kerr, Faraday and ellipticity signals for charged single quantum dots and their arrays. The microscopic theory considers both the single pump- pulse optical excitation and the effect of a train of such picosecond pulses, which in the case of long resident-electron spin coherence time leads to a stationary distribution of theelectron spin polarization. The specific feature of QD ensembles is their inhomogeneity in resonance transition energy and electron g-factor value, which results in fast dephasing of spin signals, on the one hand, and leads to spin revival before the next pulse arrives (the so-called spin mode locking), on the other hand. The theory is applied to describe the time- resolved single-color and two-color pump-probe experiments performed on InGaAs/GaAs quantum dots.
