Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 36: Poster Ib

HL 36.16: Poster

Dienstag, 8. März 2016, 15:00–19:00, Poster A

Impact of the nuclear spin bath on the carrier spin noise in InGaAs/GaAs self-assembled quantum dots — •Philipp Glasenapp¹, Dmitri Smirnov², Mikhail Glazov², Alex Greilich¹, Johannes Hackmann¹, Frithjof Anders¹, and Manfred Bayer¹ — ¹Technische Universität Dortmund, 44227 Dortmund, Germany — ²Ioffe Physical-Technical Institute, 194021 St. Petersburg, Russia

Spin noise of self-assembled InGaAs/GaAs quantum dots doped with single electron or hole spins, and grown under identical conditions, is measured optically in the limit of low probe laser intensity. This allows to reveal fundamental properties of carrier spin dynamics due to interaction with surrounding nuclei on a level close to thermal equilibrium. These dynamics include for example Overhauser precession of electron spins due to isotropic hyperfine interaction. The most remarkable result is the decoupling of the carrier spins from the nuclei under longitudinal magnetic fields, leading to a crossover to 1/log (t) spin dynamics. This happens regardless of the type of carrier spin, and we find that under these conditions both electrons and holes obey comparable timescales of dephasing - an observation that can be seen as an evidence of nuclear quadrupolar effects in the quantum dots that do not depend on carrier spin doping, and which provide additional channels of spin dephasing beyond hyperfine interaction. We compare our results to existing theoretical models and find good agreement.