Dresden 2011 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

HL: Fachverband Halbleiterphysik

HL 71: Quantum Dots: Optical Properties

HL 71.6: Vortrag

Donnerstag, 17. März 2011, 11:45–12:00, POT 251

Off-resonant generation of electron spin coherence in InAs quantum dots — •Britt-Marie Meiners¹, Alexander Schwan¹, Stefan Spatzek¹, Steffen Varwig¹, Dmitri Yakovlev¹, Andre Henriques², and Manfred Bayer¹ — ¹Experimentelle Physik 2, U Dortmund,D-44227 Dortmund, Germany — ²Instituto de Física, Universidade de São Paulo, 05315-970 São Paulo, SP, Brazil

Studies of electron spin dynamics in solids have recently become a rapidly developing field of condensed-matter physics. We studied electron spin coherence in an inhomogeneous ensemble of singly charged (In,Ga)As/GaAs QDs by means of time-resolved techniques. The temporal evolution of the spin precession is measured by two-colour Faraday rotation and ellipticity.

Excitation energy was varied in an wide range up to 100 meV above the QDs resonances and even beyond the GaAs barrieer band gap, while the signal was detected on QD trion resonances. Surprisingly, we find that the electron spin coherence can be very efficiently excited even for strong detuning of the pump laser energy. This means that the electrons do not loose their spin coherence in the course of the energy relaxation of more than 100 meV.Also energy dispersion of the electron g-factors across the QD photoluminescence band has been measured and analyzed.