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We address the temperature influence on the precessional motion of electron spins under transverse magnetic field, studied in a GaAs/AlGaAs triple quantum wells, using pump-probe Kerr rotation. In the presence of an applied in-plane…

Mesoscale and Nanoscale Physics · Physics 2018-05-18 S. Ullah , F. C. D. Moraes , G. M. Gusev , A. K. Bakarov , F. G. G. Hernandez

We study high-field spin transport of electrons in a quasi one-dimensional channel of a $GaAs$ gate controlled spin interferometer (SPINFET) using a semiclassical formalism (spin density matrix evolution coupled with Boltzmann transport…

Mesoscale and Nanoscale Physics · Physics 2009-09-29 S. Pramanik , S. bandyopadhyay , M. Cahay

The dynamic polarization of nuclear spins by photoexcited electrons is studied in a high quality GaAs/AlGaAs quantum well. We find a surprisingly high efficiency of the spin transfer from the electrons to the nuclei as reflected by a…

Mesoscale and Nanoscale Physics · Physics 2017-11-15 R. W. Mocek , V. L. Korenev , M. Bayer , M. Kotur , R. I. Dzhioev , D. O. Tolmachev , G. Cascio , K. V. Kavokin , D. Suter

We have studied the possibly half metallic Co2FeSi full Heusler alloy by means of spin- and time-resolved photoemission spectroscopy. For excitation, the second and fourth harmonic of femtosecond Ti:sapphire lasers were used, with photon…

Materials Science · Physics 2016-08-16 J. -P. Wüstenberg , M. Cinchetti , M. Sánchez Albaneda , M. Bauer , M. Aeschlimann

Density-functional calculations using an exact exchange potential for a two-dimensional electron gas (2DEG) formed in a GaAs single quantum well predict the existence of a spin-polarized phase, when an excited subband becomes slightly…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 A. R. Goñi , P. Giudici , F. A. Reboredo , C. R. Proetto , C. Thomsen , K. Eberl , M. Hauser

We derive a drift-diffusion equation for spin polarization in semiconductors by consistently taking into account electric-field effects and nondegenerate electron statistics. We identify a high-field diffusive regime which has no analogue…

Materials Science · Physics 2009-11-07 Z. G. Yu , M. E. Flatte

Irradiating a semiconductor with circularly polarized light creates spin-polarized charge carriers. If the material contains atoms with non-zero nuclear spin, they interact with the electron spins via the hyperfine coupling. Here, we…

Mesoscale and Nanoscale Physics · Physics 2016-09-09 Raphael W. Mocek , Danil O. Tolmachev , Giovanni Cascio , Dieter Suter

We present a detailed experimental and theoretical analysis of the spin dynamics of two-dimensional electron gases (2DEGs) in a series of n-doped GaAs/AlGaAs quantum wells. Picosecond-resolution polarized pump-probe reflection techniques…

Mesoscale and Nanoscale Physics · Physics 2015-06-25 W. J. H. Leyland , G. H. John , R. T. Harley , M. M. Glazov , E. L. Ivchenko , D. A. Ritchie , A. J. Shields , M. Henini

Nuclear spin polarization dynamics are measured in optically pumped individual GaAs/AlGaAs interface quantum dots by detecting the time-dependence of the Overhauser shift in photoluminescence (PL) spectra. Long nuclear polarization decay…

The electron spin dynamics in an optically excited narrow quantum well is studied, where the electron spins precess in a k-dependent magnetic field while the electrons scatter at localized impurities. For the resulting spin decay, which is…

Mesoscale and Nanoscale Physics · Physics 2017-05-31 Michael Cosacchi , Moritz Cygorek , Florian Ungar , Vollrath Martin Axt

We report on a picosecond-fast optical removal of spin polarization from a self-confined photo-carrier system at an undoped GaAs/AlGaAs interface possessing superior long-range and high-speed spin transport properties. We employed a…

Other Condensed Matter · Physics 2017-10-04 L. Nádvorník , M. Surýnek , K. Olejník , V. Novák , J. Wunderlich , F. Trojánek , T. Jungwirth , P. Němec

We present a microscopic theory for transport of the spin polarized charge density wave with both electrons and holes in the $(111)$ GaAs quantum wells. We analytically show that, contradicting to the commonly accepted belief, the spin and…

Mesoscale and Nanoscale Physics · Physics 2013-11-27 M. Q. Weng , M. W. Wu

A drift-diffusion model for spin-charge transport in spin-polarized {\it p-n} junctions is developed and solved numerically for a realistic set of material parameters based on GaAs. It is demonstrated that spin polarization can be injected…

Materials Science · Physics 2009-11-07 Igor Zutic , Jaroslav Fabian , S. Das Sarma

Hyperpolarized nanoparticles (NPs) offer high polarization levels with room temperature relaxation times exceeding half an hour. In this work, we demonstrate that the achievable hyperpolarization enhancement and relaxation (decay) time at…

We investigate spin polarized electron transport in ultra-thin Si-Core/Ge-Shell and Ge-Core/Si-Shell nanowire system using semi-classical Monte Carlo simulation method. Depolarization of electron's spin occurs in nanowire mainly due to…

Mesoscale and Nanoscale Physics · Physics 2016-04-13 Bhupesh Bishnoi , Bahniman Ghosh

It is shown that focusing circularly-polarized 800 nm light pulses of 100 fs duration on the tips of p-GaAs crystalline shards having no negative electron affinity (NEA) activation results in electron emission that is both fast and…

Optics · Physics 2019-03-27 Evan Brunkow , Eric R. Jones , Herman Batelaan , T. J. Gay

The spin relaxation time of electrons in GaAs and GaN are determined with a model that includes momentum scattering by phonons and ionized impurities, and spin scattering by the Elliot-Yafet, D'yakonov-Perel, and Bir-Aronov-Pikus…

Materials Science · Physics 2009-11-10 S. Krishnamurthy , N. Newman , M. van Schilfgaarde

We show by spatially and time-resolved photoluminescence that the application of an electric field transverse to the plane of an intrinsic GaAs (111) quantum well (QW) allows the transport of photogenerated electron spins polarized along…

Mesoscale and Nanoscale Physics · Physics 2019-03-13 A. Hernández-Mínguez , K. Biermann , R. Hey , P. V. Santos

We have demonstrated by electroluminescence the injection of spin polarized electrons through Co/Al2O3/GaAs tunnel barrier into p-doped InAs/GaAs quantum dots embedded in a PIN GaAs light emitting diode. The spin relaxation processes in the…

This paper presents a study of electron spin dynamics in bulk GaAs at low temperatures for elevated optical excitation conditions. Our time-resolved Faraday rotation measurements yield sub-nanosecond electron spin dephasing-times over a…

Materials Science · Physics 2015-05-13 M. Krauss , R. Bratschitsch , Z. Chen , S. T. Cundiff , H. C. Schneider