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Related papers: Determination of spin polarization in InAs/GaAs se…

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We report electrical control of the spin polarization of InAs/GaAs self-assembled quantum dots (QDs) at room temperature. This is achieved by electrical injection of spin-polarized electrons from an Fe Schottky contact. The circular…

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

Using a `standard' NMR spin-echo technique we determined the spin polarization of two-dimensional electrons, confined to GaAs quantum wells, from the hyperfine shift of Ga nuclei in the wells. Concentrating on the temperature and magnetic…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 S. Melinte , N. Freytag , M. Horvatic , C. Berthier , L. P. Levy , V. Bayot , M. Shayegan

One and two-electron systems confined in a single and coupled quantum dots defined within a nanowire with a finite radius are studied in the context of spin-orbit coupling effects. Anisotropy of the spin-orbit interaction is discussed in…

Mesoscale and Nanoscale Physics · Physics 2013-05-30 M. P. Nowak , B. Szafran

We have made quantitative measurements of the spin polarization of two-dimensional (2D) GaAs (100) electrons and GaAs (311)A holes, as a function of an in-plane magnetic field. The functional form of the in-plane magnetoresistance is shown…

Mesoscale and Nanoscale Physics · Physics 2015-06-24 E. Tutuc , E. P. De Poortere , S. J. Papadakis , M. Shayegan

We report on the dynamic nuclear polarization of a single charge-tunable self-assembled InAs/GaAs quantum dot in a longitudinal magnetic field of $\sim$0.2T. The hyperfine interaction between the optically oriented electron and nuclei spins…

We present a detailed experimental and theoretical analysis of the optical orientation of electron spins in GaAs/AlAs quantum wells. Using time and polarization resolved photoluminescence excitation spectroscopy, the initial degree of…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 S. Pfalz , R. Winkler , T. Nowitzki , D. Reuter , A. D. Wieck , D. Haegele , M. Oestreich

We suggest a new spin orientation mechanism for localized electrons: $dynamic~electron~spin~polarization~provided~by~nuclear~spin~fluctuations$. The angular momentum for the electrons is gained from the nuclear spin system via the hyperfine…

Mesoscale and Nanoscale Physics · Physics 2020-10-14 D. S. Smirnov , T. S. Shamirzaev , D. R. Yakovlev , M. Bayer

A fourteen-fold anisotropy in the spin transport efficiency parallel and perpendicular to the charge transport is observed in a vertically-biased (Ga,Mn)As-based spin-polarized light emitting diode. The spin polarization is determined by…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 D. K. Young , E. Johnston-Halperin , D. D. Awschalom , Y. Ohno , H. Ohno

We propose a novel scheme to efficiently polarize and manipulate the electron spin in a quantum dot. This scheme is based on the spin-orbit interaction and it possesses following advantages: (1) The direction and the strength of the spin…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Qing-feng Sun , X. C. Xie

Two-dimensional (2D) electrons in an in-plane magnetic field become fully spin polarized above a field B_P, which we can determine from the in-plane magnetoresistance. We perform such measurements in modulation-doped AlAs electron systems,…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 E. P. De Poortere , E. Tutuc , Y. P. Shkolnikov , K. Vakili , M. Shayegan

We demonstrate that non-equilibrium electrons in thin nonmagnetic semiconductor layers or quantum dots can be fully spin polarized by means of simultaneous electrical spin injection and extraction. The complete spin polarization is achieved…

Other Condensed Matter · Physics 2009-11-11 V. V. Osipov , A. G. Petukhov , V. N. Smelyanskiy

We report the observation of an anomalous conductance plateau near G = 0.5 G0 (G0 = 2e2/h) in asymmetrically biased AlGaAs/GaAs quantum point contacts (QPCs), with in-plane side gates in the presence of lateral spin-orbit coupling. This is…

Mesoscale and Nanoscale Physics · Physics 2012-04-24 N. Bhandari , P. P. Das , M. Cahay , R. S. Newrock , S. T. Herbert

We report electronic control and measurement of an imbalance between spin-up and spin-down electrons in micron-scale open quantum dots. Spin injection and detection was achieved with quantum point contacts tuned to have spin-selective…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 E. J. Koop , B. J. van Wees , D. Reuter , A. D. Wieck , C. H. van der Wal

The total energy of a quasi-one-dimensional electron system is calculated using density functional theory. It is shown that spontaneous ferromagnetic state in quantum wire occurs at low one-dimensional electron density. The critical…

Mesoscale and Nanoscale Physics · Physics 2013-01-14 A. A. Vasilchenko

Inelastic spin relaxation and spin splitting $\epsilon_{\mathrm{s}}$ in lateral quantum dots are studied in the regime of strong in-plane magnetic field. Due to both g-factor energy dependence and spin-orbit coupling $\epsilon_{\mathrm{s}}$…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Vladimir I. Fal'ko , B. L. Altshuler , O. Tsyplyatev

The temperature-dependent electron spin relaxation of positively charged excitons in a single InAs quantum dot (QD) was measured by time-resolved photoluminescence spectroscopy at zero applied magnetic fields. The experimental results show…

Mesoscale and Nanoscale Physics · Physics 2015-06-03 X. M. Dou , B. Q. Sun , D. S. Jiang , H. Q. Ni , Z. C. Niu

We investigate how the strain-induced nuclear quadrupole interaction influences the degree of nuclear spin polarization in self-assembled quantum dots. Our calculation shows that the achievable nuclear spin polarization in In_{x}Ga_{1-x}As…

Mesoscale and Nanoscale Physics · Physics 2013-05-29 Chia-Wei Huang , Xuedong Hu

We show that ionization of noble gas atoms by strong infrared circularly polarized laser field under standard exerimental conditions can yield electrons with up to 100% spin polarization in energy resolved measurements. Spin polarization…

Atomic Physics · Physics 2013-07-18 Ingo Barth , Olga Smirnova

The magnetization of quantum dots is discussed in terms of a relatively simple but exactly solvable model Hamiltonian. The model predicts oscillations in spin polarization as a function of dot radius for a fixed electron density. These…

Mesoscale and Nanoscale Physics · Physics 2007-10-11 A. Bansil , D. Nissenbaum , B. Barbiellini , R. Saniz
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