Dresden 2014 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 25: Focus Session: Electron Spin Qubits in Semiconductor Quantum Dots (organized by HL)
TT 25.9: Talk
Monday, March 31, 2014, 18:00–18:15, POT 051
Optical Spin Noise of a Single Hole in a Quantum Dot — •Ramin Dahbashi1, Jens Hübner1, Fabian Berski1, Klaus Pierz2, and Michael Oestreich1 — 1Institute for Solid State Physics, Leibniz Universität Hannover, Appelstr. 2, D-30167 Hannover, Germany — 2Physikalisch Technische Bundesanstalt, Bundesallee 100, D-38116 Braunschweig, Germany
We present spin noise spectroscopy (SNS) [1] at the extreme limit of single spin detection, i.e., measurements of the spin dynamics of a single heavy hole localized in a self-assembled (InGa)As quantum dot (QD) [2]. Magnetic field dependent measurements reveal a strong dependence of the heavy hole spin relaxation rate T1−1 on the longitudinal external magnetic field (∝ Bz−3/2) even for very low magnetic fields up to 31 mT. At very low probe light intensities we detect an extremely long T1 of > 180 µs at 31 mT and 5 K. The inhomogeneously broadening of a single QD SN spectrum is unveiled by the probe energy dependence of the SN power for finite light intensities. This feature is explained by charge fluctuations in the QD vicinity leading to distinct charge configurations. The corresponding fluctuations of the QD resonance energy are corroborated by a distinct probe intensity dependence of the spin lifetime. We further investigate time correlation effects of single QD SN spectra to gain insight into charging dynamics in the surrounding.
[1] Müller et al., Physica E 43, 569 (2010).
[2] Dahbashi et al., arXiv:1306.3183 (2013).
[3] Dahbashi et al., Appl. Phys. Lett. 100, 031906 (2012).