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Related papers: Suppression of nuclear spin diffusion at a GaAs/Al…

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We propose a new mechanism for polarizing nuclear spins in quantum dots, based on periodic modulation of the hyperfine coupling by electric driving at the electron spin resonance frequency. Dynamical nuclear polarization results from…

Mesoscale and Nanoscale Physics · Physics 2008-04-14 M. S. Rudner , L. S. Levitov

We present spin noise (SN) measurements on an ensemble of donor-bound electrons in ultrapure GaAs:Si covering temporal dynamics over six orders of magnitude from milliseconds to nanoseconds. The SN spectra detected at the donor-bound…

Mesoscale and Nanoscale Physics · Physics 2015-10-28 Fabian Berski , Jens Hübner , Michael Oestreich , Arne Ludwig , A. D. Wieck , Mikhail Glazov

We theoretically investigate dynamic nuclear spin polarization in a self-assembled quantum dot pumped optically by two laser beams. With the assumption that a noncollinear interaction between the hole spin and nuclear spins leads to nuclear…

Mesoscale and Nanoscale Physics · Physics 2013-06-07 Xiao-Feng Shi

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

We demonstrate the suppression of nuclear spin fluctuations in an InAs quantum dot and measure the timescales of the spin narrowing effect. By initializing for tens of milliseconds with two continuous wave diode lasers, fluctuations of the…

Mesoscale and Nanoscale Physics · Physics 2015-06-04 Bo Sun , Colin Ming Earn Chow , Duncan G. Steel , Allan S. Bracker , Daniel Gammon , L. J. Sham

Conduction electrons are used to optically polarize, detect and manipulate nuclear spin in a (110) GaAs quantum well. Using optical Larmor magnetometry, we find that nuclear spin can be polarized along or against the applied magnetic field,…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 G. Salis , D. T. Fuchs , J. M. Kikkawa , D. D. Awschalom , Y. Ohno , H. Ohno

Transport through spin-blockaded quantum dots provides a means for electrical control and detection of nuclear spin dynamics in the host material. Although such experiments have become increasingly popular in recent years, interpretation of…

Mesoscale and Nanoscale Physics · Physics 2011-08-22 M. S. Rudner , F. H. L. Koppens , J. A. Folk , L. M. K. Vandersypen , L. S. Levitov

We report on the direct measurement of the electron spin splitting and the accompanying nuclear Overhauser (OH) field, and thus the underlying nuclear spin polarization (NSP) and fluctuation bandwidth, in a single InAs quantum dot under…

Mesoscale and Nanoscale Physics · Physics 2021-01-04 Aaron M. Ross , Allan S. Bracker , Michael K. Yakes , Daniel Gammon , L. J. Sham , Duncan G. Steel

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

We present measurements on nuclear spin relaxation probed by a single quantum dot in a high-mobility electron gas. Current passing through the dot leads to a spin transfer from the electronic to the nuclear spin system. Applying electron…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 A. K. Huettel , J. Weber , A. W. Holleitner , D. Weinmann , K. Eberl , R. H. Blick

We report on both experimental and theoretical study of conduction-electron spin polarization dynamics achieved by pulsed optical pumping at room temperature in GaAs(1-x)N(x) alloys with a small nitrogen content (x = 2.1, 2.7, 3.4%). It is…

Materials Science · Physics 2015-06-25 V. K. Kalevich , A. Yu. Shiryaev , E. L. Ivchenko , A. Yu. Egorov , L. Lombez , D. Lagarde , X. Marie , T. Amand

We use optical transient-grating spectroscopy to measure spin diffusion of optically oriented electrons in bulk, semi-insulating GaAs(100). Trapping and recombination do not quickly deplete the photoexcited population. The spin diffusion…

Materials Science · Physics 2011-11-01 C. P. Weber , Craig A. Benko , Stanley C. Hiew

We have studied spin dephasing and spin diffusion in a high-mobility two-dimensional electron system, embedded in a GaAs/AlGaAs quantum well grown in the [110] direction, by a two-beam Hanle experiment. For very low excitation density, we…

Mesoscale and Nanoscale Physics · Physics 2011-07-01 R. Völkl , M. Griesbeck , S. A. Tarasenko , D. Schuh , W. Wegscheider , C. Schüller , T. Korn

We show that optical pumping of electron spins in individual InGaAs quantum dots leads to strong nuclear polarisation that we measure via the Overhauser shift (OHS) in magneto-photoluminescence experiments between 0 and 4T. We find a…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 P. -F. Braun , B. Urbaszek , T. Amand , X. Marie , O. Krebs , B. Eble , A. Lemaitre , P. Voisin

In self assembled III-V semiconductor quantum dots, valence holes have longer spin coherence times than the conduction electrons, due to their weaker coupling to nuclear spin bath fluctuations. Prolonging hole spin stability relies on a…

Mesoscale and Nanoscale Physics · Physics 2016-09-14 M. Vidal , M. V. Durnev , L. Bouet , T. Amand , M. M. Glazov , E. L. Ivchenko , P. Zhou , G. Wang , T. Mano , T. Kuroda , X. Marie , K. Sakoda , B. Urbaszek

The study of nuclear magnetic resonance and nuclear spin-lattice relaxation was conducted in an asymmetrically doped to $n\sim1.8\times10^{11}$ cm$^{-2}$ 16 nm AlAs quantum well grown in the $[001]$-direction. Dynamic polarization of…

Mesoscale and Nanoscale Physics · Physics 2016-12-22 A. V. Shchepetilnikov , D. D. Frolov , Yu. A. Nefyodov , I. V. Kukushkin , D. S. Smirnov , L. Tiemann , C. Reichl , W. Dietsche , W. Wegscheider

Spin-blockaded quantum dots provide a unique setting for studying nuclear-spin dynamics in a nanoscale system. Despite recent experimental progress, observing phase-sensitive phenomena in nuclear spin dynamics remains challenging. Here we…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 M. S. Rudner , I. Neder , L. S. Levitov , B. I. Halperin

This study investigated the formation and relaxation dynamics of nuclear spin polarization in three Al$_x$Ga$_{1-x}$As bulk samples with different aluminum concentrations $x$ of 0.00, 0.05, and 0.15. The time-resolved Kerr rotation…

Materials Science · Physics 2026-02-20 A. Shen , J. Chen , R. Kaji , S. Yamamoto , H. Sasakura , T. Uemura , S. Adachi

The dynamics of the coupled electron-nuclear spin system is studied in an ensemble of singly-charged (In,Ga)As/GaAs quantum dots (QDs) using periodic optical excitation at 1 GHz repetition rate. In combination with the electron-nuclei…

Mesoscale and Nanoscale Physics · Physics 2021-08-11 E. Evers , N. E. Kopteva , I. A. Yugova , D. R. Yakovlev , M. Bayer , A. Greilich

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…