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2.
Phys Rev Lett ; 115(17): 176601, 2015 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-26551132

RESUMO

We present spin-noise spectroscopy measurements on an ensemble of donor-bound electrons in ultrapure GaAs:Si covering temporal dynamics over 6 orders of magnitude from milliseconds to nanoseconds. The spin-noise spectra detected at the donor-bound exciton transition show the multifaceted dynamical regime of the ubiquitous mutual electron and nuclear spin interaction typical for III-V-based semiconductor systems. The experiment distinctly reveals the finite Overhauser shift of an electron spin precession at zero external magnetic field and a second contribution around zero frequency stemming from the electron spin components parallel to the nuclear spin fluctuations. Moreover, at very low frequencies, features related with time-dependent nuclear spin fluctuations are clearly resolved making it possible to study the intricate nuclear spin dynamics at zero and low magnetic fields. The findings are in agreement with the developed model of electron and nuclear spin noise.

3.
Phys Rev Lett ; 112(15): 156601, 2014 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-24785063

RESUMO

We advance spin noise spectroscopy to the ultimate limit of single spin detection. This technique enables the measurement of the spin dynamic of a single heavy hole localized in a flat (InGa)As quantum dot. Magnetic field and light intensity dependent studies reveal even at low magnetic fields a strong magnetic field dependence of the longitudinal heavy hole spin relaxation time with an extremely long T1 of ≥180 µs at 31 mT and 5 K. The wavelength dependence of the spin noise power discloses for finite light intensities an inhomogeneous single quantum dot spin noise spectrum which is explained by charge fluctuations in the direct neighborhood of the quantum dot. The charge fluctuations are corroborated by the distinct intensity dependence of the effective spin relaxation rate.

4.
Phys Rev Lett ; 111(18): 186602, 2013 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-24237545

RESUMO

We advance all optical spin noise spectroscopy (SNS) in semiconductors to detection bandwidths of several hundred gigahertz by employing a sophisticated scheme of pulse trains from ultrafast laser oscillators as an optical probe. The ultrafast SNS technique avoids the need for optical pumping and enables nearly perturbation free measurements of extremely short spin dephasing times. We apply the technique to highly-n-doped bulk GaAs where magnetic field dependent measurements show unexpected large g-factor fluctuations. Calculations suggest that such large g-factor fluctuations do not necessarily result from extrinsic sample variations but are intrinsically present in every doped semiconductor due to the stochastic nature of the dopant distribution.

5.
Opt Express ; 21(5): 5872-8, 2013 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-23482155

RESUMO

We combine the scanning temporal ultrafast delay (STUD) technique with spin noise spectroscopy (SNS), which is based upon below band gap Faraday rotation to investigate the full temporal dynamics of stochastically orientated electron spins in slightly n-doped bulk GaAs. The application of STUD-SNS boosts the common technical bandwidth limitation of the electro-optic conversion in cw-SNS into the several hundred GHz regime. Numerical simulations highlight the strengths and examine the limitations of STUD-SNS.

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