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NMR measurements of the electron spin polarization have been performed on a 2D electron system at and around half-filled lowest Landau level. Comparing the magnetic field and the temperature dependence of the spin polarization to models of…

Mesoscale and Nanoscale Physics · Physics 2016-08-16 N. Freytag , M. Horvatić , C. Berthier , M. Shayegan , L. P. Lévy

The Knight shift and the nuclear spin-lattice relaxation rate 1/T1 of Ga-71 nuclei are measured in GaAs quantum wells at Landau level filling factor nu = 1/2 using optically pumped NMR. The temperature dependences of these data are compared…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 A. E. Dementyev , N. N. Kuzma , P. Khandelwal , S. E. Barrett , L. N. Pfeiffer , K. W. West

The Knight shift of Ga-71 nuclei is measured in two different electron-doped multiple quantum well samples using optically pumped NMR. These data are the first direct measurements of the electron spin polarization,…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 P. Khandelwal , N. N. Kuzma , S. E. Barrett , L. N. Pfeiffer , K. W. West

The average electron spin-polarization $\cal P$ of two-dimensional electron gas confined in $\rm GaAs/GaAlAs$ multiple quantum-wells was measured by nuclear magnetic resonance (NMR) near the fractional quantum Hall state with filling factor…

Mesoscale and Nanoscale Physics · Physics 2019-08-17 N. Freytag , Y. Tokunaga , M. Horvatic , C. Berthier , M. Shayegan , L. Levy

The transition from partial to complete spin polarization of two-dimensional electrons at half filling of the lowest Landau level has been studied using resistively-detected nuclear magnetic resonance (RDNMR). The nuclear spin-lattice…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 L. A. Tracy , J. P. Eisenstein , L. N. Pfeiffer , K. W. West

Hyperfine interactions between electron and nuclear spins in the quantum Hall regime provide powerful means for manipulation and detection of nuclear spins. In this work we demonstrate that significant changes in nuclear spin polarization…

Mesoscale and Nanoscale Physics · Physics 2015-06-05 Y. Q. Li , V. Umansky , K. von Klitzing , J. H. Smet

Enhancement of the electron spin polarization in a correlated two-layer two-dimensional electron system at a total Landau level filling factor of one is reported. Using resistively detected nuclear magnetic resonance, we demonstrate that…

Strongly Correlated Electrons · Physics 2015-04-30 L. Tiemann , W. Wegscheider , M. Hauser

Polarization-resolved magneto-luminescence, together with simultaneous magneto-transport measurements, have been performed on a two-dimensional electron gas (2DEG) confined in CdTe quantum well in order to determine the spin-splitting of…

Mesoscale and Nanoscale Physics · Physics 2015-05-19 J. Kunc , K. Kowalik , F. J. Teran , P. Plochocka , B. A. Piot , D. K. Maude , M. Potemski , V. Kolkovsky , G. Karczewski , T. Wojtowicz

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

The magnetoresistance of a low carrier density, disordered GaAs based two-dimensional (2D) electron gas has been measured in parallel magnetic fields up to 32 T. The feature in the resistance associated with the complete spin polarization…

Mesoscale and Nanoscale Physics · Physics 2009-11-09 B. A. Piot , D. K. Maude , U. Gennser , A. Cavanna , D. Mailly

The spin polarization of electrons trapped in InAs self-assembled quantum dot ensembles is investigated. A statistical approach for the population of the spin levels allows one to infer the spin polarization from the measure values of the…

Materials Science · Physics 2008-04-04 F. G. G. Hernandez , T. P. Mayer Alegre , G. Medeiros-Ribeiro

Measurements in clean two-dimensional electron systems confined to wide GaAs quantum wells in which two electric subbands are occupied reveal an unexpected rotation of the orientation of the stripe phase observed at a half-filled Landau…

Mesoscale and Nanoscale Physics · Physics 2014-09-23 Yang Liu , D. Kamburov , M. Shayegan , L. N. Pfeiffer , K. W. West , K. W. Baldwin

We apply polarization resolved photoluminescence spectroscopy to measure the spin polarization of a two dimensional electron gas in perpendicular magnetic field. In the vicinity of filling factor nu=5/2, we observe a sharp discontinuity in…

Mesoscale and Nanoscale Physics · Physics 2015-05-19 M. Stern , P. Plochocka , V. Umansky , D. K. Maude , M. Potemski , I. Bar-Joseph

Inversion asymmetry induced spin splitting of the electron states in quasi two-dimensional (2D) systems can be attributed to an effective magnetic field B which varies in magnitude and orientation as a function of the in-plane wave vector…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 R. Winkler

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 present longitudinal and Hall magneto-resistance measurements of a ``magnetic'' two-dimensional electron gas (2DEG) formed in modulation-doped Zn$_{1-x-y}$Cd$_{x}$Mn$_{y}$Se quantum wells. The electron spin splitting is temperature and…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 R. Knobel , N. Samarth , J. G. E. Harris , D. D. Awschalom

We study the critical spin-polarization energy ($\alpha_{\rm C}$) above which fractional quantum Hall states in two-dimensional electron systems confined to symmetric GaAs quantum wells become fully spin-polarized. We find a significant…

Mesoscale and Nanoscale Physics · Physics 2014-09-23 Yang Liu , S. Hasdemir , A. Wójs , J. K. Jain , L. N. Pfeiffer , K. W. West , K. W. Baldwin , M. Shayegan

The formation of a novel spin-polarized 2D electron gas at the LaMnO$_3$ monolayer embedded in SrMnO$_3$ is predicted from the first-principles density-functional calculations. The La (d) electrons become confined in the direction normal to…

Materials Science · Physics 2010-03-10 B. R. K. Nanda , S. Satpathy

We report electrical transport measurements in a tilted magnetic field on a high-mobility two-dimensional electron system confined at the MgZnO/ZnO heterointerface. The observation of multiple crossing events of spin-resolved Landau levels…

Mesoscale and Nanoscale Physics · Physics 2015-06-23 D. Maryenko , J. Falson , Y. Kozuka , A. Tsukazaki , M. Kawasaki

We investigate the local spin polarization texture of Landau levels under Rashba spin-orbit coupling in bulk two-dimensional electron gas (2DEG) systems. In order to analyze the spin polarization as a function of two-dimensional coordinates…

Mathematical Physics · Physics 2010-06-25 T. Fujita , M. B. A. Jalil , S. G. Tan , F. Wan
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