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We demonstrate a scheme for optically patterning nuclear spin polarization in semiconductor/ferromagnet heterostructures. A scanning time-resolved Kerr rotation microscope is used to image the nuclear spin polarization that results when…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 J. Stephens , J. Berezovsky , R. K. Kawakami , A. C. Gossard , D. D. Awschalom

We find that photoexcited electrons in an n-GaAs epilayer rapidly (< 50 ps) spin-polarize due to the proximity of an epitaxial ferromagnetic metal. Comparison between MnAs/GaAs and Fe/GaAs structures reveals that this coherent spin…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 R. J. Epstein , I. Malajovich , R. K. Kawakami , Y. Chye , M. Hanson , P. M. Petroff , A. C. Gossard , D. D. Awschalom

We measure the statistical polarization of quadrupolar nuclear spins in a sub-micrometer (0.6 um^3) particle of GaAs using magnetic resonance force microscopy. The crystalline sample is cut out of a GaAs wafer and attached to a…

Mesoscale and Nanoscale Physics · Physics 2016-11-25 Fei Xue , D. P. Weber , P. Peddibhotla , M. Poggio

We demonstrate one-dimensional nuclear magnetic resonance imaging of the semiconductor GaAs with 170 nanometer slice separation and resolve two regions of reduced nuclear spin polarization density separated by only 500 nanometers. This is…

Instrumentation and Detectors · Physics 2009-11-07 Kent R. Thurber , Lee E. Harrell , Doran D. Smith

The effect of uniaxial tensile strain on spin coherence in n-type GaAs epilayers is probed using time-resolved Kerr rotation, photoluminescence, and optically-detected nuclear magnetic resonance spectroscopies. The bandgap, electron spin…

Materials Science · Physics 2009-11-11 H. Knotz , A. W. Holleitner , J. Stephens , R. C. Myers , D. D. Awschalom

We demonstrate methods to locally control the spin rotation of moving electrons in a GaAs channel. The Larmor frequency of optically-injected spins is modulated when the spins are dragged through a region of spin-polarized nuclei created at…

Mesoscale and Nanoscale Physics · Physics 2015-05-19 M. E. Nowakowski , G. D. Fuchs , S. Mack , N. Samarth , D. D. Awschalom

Recently reported optical nuclear orientation in the $n$-doped GaAs microcavity under pumping in nominal transparency region of the crystal [Appl. Phys. Lett. $\mathbf{106}$, 242405 (2015)] has arisen a number of questions, the main of them…

We investigate the dynamic nuclear polarization from the hyperfine interaction between nonequilibrium electronic spins and nuclear spins coupled to them in semiconductor nanostructures. We derive the time and position dependence of the…

Materials Science · Physics 2007-05-23 Ionel Tifrea , Michael E. Flatte

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 demonstrate the epitaxial growth of optical-quality electrically-gated III-V ferromagnetic quantum structures. Photoluminescence spectroscopy reveals that initially unpolarized photoexcited holes in a GaAs quantum well become…

Materials Science · Physics 2007-05-23 R. C. Myers , A. C. Gossard , D. D. Awschalom

Optical pump-probe techniques are used to generate and measure electron spin polarization in a gallium arsenide epilayer in which the electron spin coherence time exceeds the mode-locked laser repetition period. Resonant spin amplification…

Mesoscale and Nanoscale Physics · Physics 2020-09-14 Michael Macmahon , Joseph R. Iafrate , Michael J. Dominguez , Vanessa Sih

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 exploit spin noise spectroscopy (SNS) to directly observe build-up of dynamic nuclear polarization and relaxation of a perturbed nuclear spin-system to its equilibrium state in a single-shot experiment. The SNS experiments were performed…

The periodic optical orientation of electron spins in (In,Ga)As/GaAs quantum dots leads to the formation of electron spin precession modes about an external magnetic field which are resonant with the pumping periodicity. As the electron…

Mesoscale and Nanoscale Physics · Physics 2019-08-15 E. Evers , V. V. Belykh , N. E. Kopteva , I. A. Yugova , A. Greilich , D. R. Yakovlev , D. Reuter , A. D. Wieck , M. Bayer

We applied the recently developed technique of force-detected nuclear magnetic resonance (NMR) to observe 71Ga, 69Ga, and 75As in GaAs. The nuclear spin-lattice relaxation time is 21$\pm$5 min for 69Ga at $\sim 5$ K and 4.6 Tesla. We have…

Materials Science · Physics 2009-11-07 Kent R. Thurber , Lee E. Harrell , Raul Fainchtein , Doran D. Smith

We use time-resolved detection of the Hanle effect and polarized photoluminescence with dark intervals to investigate the buildup and decay of the spin polarization of nuclei interacting with donor-bound electrons in $n$-doped GaAs. Strong…

Mesoscale and Nanoscale Physics · Physics 2019-02-21 P. S. Sokolov , M. Yu. Petrov , K. V. Kavokin , M. S. Kuznetsova , S. Yu. Verbin , I. Ya. Gerlovin , D. R. Yakovlev , M. Bayer

We study light-induced nuclear spin-polarization in a thin film of Ga1-xMnxAs (x 0.04), a dilute ferromagnetic semiconductor, grown on a GaAs substrate. High-field inductively-detected Ga-71 NMR was performed with samples immersed in…

Measurements and modeling of electron spin transport and dynamics are used to characterize hyperfine interactions in Fe/GaAs devices with $n$-GaAs channels. Ga and As nuclei are polarized by electrically injected electron spins, and the…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 M. K. Chan , Q. O. Hu , J. Zhang , T. Kondo , C. J. Palmstrøm , P. A. Crowell

A ring structure fabricated from GaAs is used to achieve interference of the net spin polarization of conduction band electrons. Optically polarized spins are split into two packets by passing through two arms of the ring in the diffusive…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Y. K. Kato , R. C. Myers , A. C. Gossard , D. D. Awschalom

We use spatial spin separation by a magnetic focusing technique to probe the polarization of quantum point contacts. The point contacts are fabricated from p-type GaAs/AlGaAs heterostructures. A finite polarization is measured in the…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 L. P. Rokhinson , L. N. Pfeiffer , K. W. West
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