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For the realisation of scalable solid-state quantum-bit systems, spins in semiconductor quantum dots are promising candidates. A key requirement for quantum logic operations is a sufficiently long coherence time of the spin system.…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 T. Korn , M. Kugler , M. Griesbeck , R. Schulz , A. Wagner , M. Kubová , C. Gerl , D. Schuh , W. Wegscheider , C. Schüller

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

Understanding and manipulating spin polarization and transport in the vicinity of semiconductor-hosted defects is a problem of present technological and fundamental importance. Here, we use high-field magnetic resonance to monitor the…

Mesoscale and Nanoscale Physics · Physics 2014-01-14 Yunpu Li , Jonathan P. King , Jeffrey A. Reimer , Carlos A. Meriles

We report on the observation of the magneto-photogalvanic effect (MPGE) due to inter-subband transitions in (001)-oriented GaAs quantum wells. This effect is related to the gyrotropic properties of the structures. It is shown that…

The resistivity change due to electron spin resonance (ESR) absorption is investigated in a high-mobility two-dimensional electron system formed in a Si/SiGe heterostructure. Results for a specific Landau level configuration demonstrate…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Junya Matsunami , Mitsuaki Ooya , Tohru Okamoto

Spin-lattice relaxation of the nuclear spin system in p-type GaAs is studied using a three-stage experimental protocol including optical pumping and measuring the difference of the nuclear spin polarization before and after a dark interval…

Other Condensed Matter · Physics 2018-05-02 M. Kotur , R. I. Dzhioev , M. Vladimirova , R. V. Cherbunin , P. S. Sokolov , D. R. Yakovlev , M. Bayer , D. Suter , K. V. Kavokin

The far-infrared absorption of triangular and square two-dimensional quantum dots is studied by means of time simulations of the density oscillations within the time-dependent local-spin-density approximation. The absorption is spatially…

Mesoscale and Nanoscale Physics · Physics 2016-08-16 Manuel Valín-Rodríguez , Antonio Puente , Llorenç Serra

As is well known the absorption of circularly polarized light in semiconductors results in optical orientation of electron spins and helicity-dependent electric photocurrent, and the absorption of linearly polarized light is accompanied by…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 S. A. Tarasenko , E. L. Ivchenko

By monitoring changes in excitonic photoluminescence (PL) that are induced by terahertz (THz) radiation, we observe resonant THz absorption by magnetoexcitons in GaAs/AlGaAs quantum wells. Changes in the PL spectrum are explored as a…

Strongly Correlated Electrons · Physics 2009-11-07 J. Cerne , J. Kono , M. Su , M. S. Sherwin

The spin relaxation of a two-dimensional electron system (2DES) formed in a symmetric quantum well is studied theoretically when the quantum well is parallel to the (110) plane of the zinc-blende structure, the spin polarization is…

Mesoscale and Nanoscale Physics · Physics 2014-02-28 Hiroshi Akera , Hidekatsu Suzuura , Yoshiyuki Egami

We report nearly complete preservation of "spin memory" between optical absorption and photoluminescence (PL) in nanometer slabs of GaSe pumped with up to 0.2 eV excess energy. At cryogenic temperatures, the initial degree of circular…

Mesoscale and Nanoscale Physics · Physics 2015-05-22 Yanhao Tang , Wei Xie , Krishna C. Mandal , John A. McGuire , Chih-Wei Lai

We present a complete description of spin injection and detection in Fe/Al_xGa_{1-x}As/GaAs heterostructures for temperatures from 2 to 295 K. Measurements of the steady-state spin polarization in the semiconductor indicate three…

Materials Science · Physics 2009-11-10 C. Adelmann , X. Lou , J. Strand , C. J. Palmstrom , P. A. Crowell

The spin diffusion/transport in $n$-type (001) GaAs quantum well at high temperatures ($\ge120$ K) is studied by setting up and numerically solving the kinetic spin Bloch equations together with the Poisson equation self-consistently. All…

Materials Science · Physics 2007-05-23 J. L. Cheng , M. W. Wu

Spin transport of indirect excitons in GaAs/AlGaAs coupled quantum wells was observed by measuring the spatially resolved circular polarization of the exciton emission. The exciton spin transport originates from the long spin relaxation…

Mesoscale and Nanoscale Physics · Physics 2012-03-02 J. R. Leonard , Sen Yang , L. V. Butov , A. C. Gossard

The understanding of the fundamentals of spin and charge densities and currents interconversion by spin-orbit coupling can enable efficient applications beyond the possibilities offered by conventional electronics. For this purpose we…

Mesoscale and Nanoscale Physics · Physics 2018-07-04 Amin Maleki Sheikhabadi , Iryna Miatka , E. Ya. Sherman , Roberto Raimondi

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…

The spin-dependent recombination (SDR) has been observed in GaAs_{1-x}N_{x} (x = 2.1, 2.7, 3.4%) at room temperature. It reveals itself in a decrease of the edge photoluminescence (PL) intensity by more than a factor of 3 when either the…

The results of magnetoconductivity measurements in GaInAs quantum wells are presented. The observed magnetoconductivity appears due to the quantum interference, which lead to the weak localization effect. It is established that the details…

In the field of spin-controlled semiconductor lasers, massive effort has been focused upon materials with long spin relaxation times (~ns). In contrast, we demonstrate room-temperature spin-polarized ultrafast pulsed lasing in InGaAs…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 Feng-kuo Hsu , Yi-Shan Lee , Sheng-Di Lin , Chih-Wei Lai

Optical absorption measurements are used to probe the spin polarization in the integer and fractional quantum Hall effect regimes. The system is fully spin polarized only at filling factor $\nu=1$ and at very low temperatures($\sim40$ mK).…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 P. Plochocka , J. M. Schneider , D. K. Maude , M. Potemski , M. Rappaport , V. Umansky , I. Bar-Joseph , J. G. Groshaus , Y. Gallais , A. Pinczuk