Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 93: Quantum Coherence and Quantum Information Systems (joint session TT/MA)

TT 93.3: Vortrag

Donnerstag, 15. März 2018, 15:45–16:00, H 2053

Magnetic field dependency of the electron spin revival amplitude in periodically pulsed quantum dots — •Iris Kleinjohann and Frithjof Anders — Lehrstuhl für Theoretische Physik II, Technische Universität Dortmund, 44227 Dortmund

When pump-probe experiments are performed on singly charged quantum dots, the spin dynamics synchronizes with the periodic pump pulses. In experiments an external magnetic field is applied in Voigt geometry and the synchronization of spin dynamics can be observed in the electron spin polarization along the optical axis. After a pump pulse the electron spin polarization shows a complete dephasing due to the hyperfine interaction. Directly before the impact of the next pump pulse a revival of polarization occurs indicating synchronization. We describe the spin dynamics in a periodically pulsed quantum dot within the central spin model. The time evolution is calculated by a Lindblad approach and shows a revival of electron spin polarization as well as an alignment of nuclear spins. The resonance condition favors an integer or a half-integer number of electron Larmor precession over one pulse interval. The non-monotonic revival amplitude as function of the external magnetic field is related to the nuclear Zeeman term.