Dresden 2020 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 16: Poster Session Superconductivity, Cryogenic Particle Detectors, Cryotechnique

TT 16.43: Poster

Montag, 16. März 2020, 15:00–19:00, P2/EG

Influence of the nuclear quadrupolar interactions in periodically driven quantum dots — •Iris Kleinjohann and Frithjof Anders — Lehrstuhl für Theoretische Physik II, Technische Universität Dortmund, 44227 Dortmund

Periodic optical driving of the electron spin in singly charged semiconductor quantum dots generates a spin polarization and induces a synchronization of the spin dynamics with the driving frequency. An external magnetic field perpendicular to the optical axis results in the Larmor precession of electron and nuclear spins of the quantum dot ensemble. While the electron spin precession adjusts to the periodicity of optical pumping, the synchronization is transmitted to the surrounding nuclear spins via hyperfine interaction generating a non-equilibrium distribution of the Overhauser field. We describe the spin dynamics by a central spin model and employ a Lindblad equation for the time evolution between optical pulses. Due to the growth process of the quantum dot sample a strain occurs in the quantum dots entailing quadrupolar interactions in the nuclear spin bath. We extend the central spin model to include these interactions and show that the influence on the synchronization with the periodic driving depends strongly on the parameters of the quadrupolar interactions.