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The apparent metal-insulator transition is observed in a high quality two-dimensional electron system (2DES) in the strained Si quantum well of a Si/Si_{1-x}Ge_x heterostructure with mobility \mu=1.9 x 10^5 cm^2/Vs at density n=1.45 x…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 K. Lai , W. Pan , D. C. Tsui , S. A. Lyon , M. Muhlberger , F. Schaffler

We examine and identify magnetoresistance mechanisms in 2D system containing a sizable concentration of magnetic ions. We argue that some of these mechanisms can serve as a tool to measure spin polarization. Lack of spin degeneracy and…

High quality strongly correlated two-dimensional (2D) electron systems at low temperatures $T\rightarrow 0$ exhibits an apparent metal-to-insulator transition (MIT) at a large $r_s$ value around 40. We have measured the magnetoresistance of…

Mesoscale and Nanoscale Physics · Physics 2013-07-01 Jian Huang , L. N. Pfeiffer , K. W. West

$Ab$ $initio$ calculations show the presence of a strong magnetoelectric interfacial coupling in CaMnO$_3$ ultra-thin film grown on a strained BaTiO$_3$ ferroelectric film. This heterostructure presents a polarization driven magnetic…

Materials Science · Physics 2025-04-23 S. Di Napoli , A. Román , A. M. Llois , M. H. Aguirre , L. B. Steren , M. A. Barral

We study the temperature flow of conductivities in a gated GaAs two-dimensional electron gas (2DEG) containing self-assembled InAs dots and compare the results with recent theoretical predictions. By changing the gate voltage, we are able…

We evaluate the charge and longitudinal spin response functions of a two-dimensional electron gas with $e^2/r$ interactions in an arbitrary state of spin polarization, using a structurally self-consistent approach to treat exchange and…

Strongly Correlated Electrons · Physics 2015-06-24 B. Davoudi , M. P. Tosi

We have studied the strongly interacting, two-valley two-dimensional (2D) electron system in ultrahigh mobility SiGe/Si/SiGe quantum wells in parallel magnetic fields strong enough to completely polarize the electron spins thus making the…

Strongly Correlated Electrons · Physics 2020-01-15 M. Yu. Melnikov , A. A. Shashkin , V. T. Dolgopolov , S. -H. Huang , C. W. Liu , A. Y. X. Zhu , S. V. Kravchenko

The electrical transport properties of a bipolar InAs/GaSb system have been studied in magnetic field. The resistivity oscillates between insulating and metallic behaviour while the quantum Hall effect shows a digital character oscillating…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 R. J. Nicholas , K. Takashina , M. Lakrimi , B. Kardynal , S. Khym , N. J. Mason , D. M. Symons , D. K. Maude , J. C. Portal

In quasi two-dimensional (2D) hole systems with an effective spin j=3/2, heavy hole-light hole splitting results in a quantization of angular momentum perpendicular to the 2D plane. The spin polarization of quasi 2D hole systems due to an…

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

Recent measurements of the 2D Hall resistance show that the Hall coefficient is independent of the applied in-plane magnetic field, i.e., the spin-polarization of the system. We calculate the weak-field Hall coefficient and the…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 E. H. Hwang , S. Das Sarma

We provide a theoretical framework for the electric field control of the electron spin in systems with diffusive electron motion. The approach is valid in the experimentally important case where both intrinsic and extrinsic spin-orbit…

Mesoscale and Nanoscale Physics · Physics 2009-09-10 R. Raimondi , P. Schwab

A self-consistent calculation of the electronic properties of GaAlAs:Mn magnetic semiconductor quantum well structures is performed including the Hartree term and the sp-d exchange interaction with the Mn magnetic moments. The spin…

Materials Science · Physics 2009-10-31 A. Ghazali , I. C. da Cunha Lima , M. A. Boselli

The temperature dependence of 2D magnetoresistance in an applied in-plane magnetic field is theoretically considered for electrons in Si MOSFETs within the screening theory for long-range charged impurity scattering limited carrier…

Disordered Systems and Neural Networks · Physics 2007-10-09 S. Das Sarma , E. H. Hwang

Experiments on a constant-density two-dimensional hole system in a GaAs quantum well reveal that the metallic behavior observed in the zero-magnetic-field temperature dependence of the resistivity depends on the symmetry of the confinement…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 S. J. Papadakis , E. P. De Poortere , H. C. Manoharan , M. Shayegan , R. Winkler

Using symmetry breaking strain to tune the valley occupation of a two-dimensional (2D) electron system in an AlAs quantum well, together with an applied in-plane magnetic field to tune the spin polarization, we independently control the…

Strongly Correlated Electrons · Physics 2014-02-03 O. Gunawan , T. Gokmen , K. Vakili , M. Padmanabhan , E. P. De Poortere , M. Shayegan

We present a numerical study of magnetic phases of the 2D electron gas near freezing. The calculations are performed by diffusion Monte Carlo in the fixed node approximation. At variance with the 3D case we find no evidence for the…

Strongly Correlated Electrons · Physics 2009-10-31 D. Varsano , S. Moroni , G. Senatore

Density-functional calculations using an exact exchange potential for a two-dimensional electron gas (2DEG) formed in a GaAs single quantum well predict the existence of a spin-polarized phase, when an excited subband becomes slightly…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 A. R. Goñi , P. Giudici , F. A. Reboredo , C. R. Proetto , C. Thomsen , K. Eberl , M. Hauser

Bilayer two-dimensional electron systems formed by a thin barrier in the GaAs buffer of a standard heterostructure were investigated by magnetotransport measurements. In magnetic fields oriented parallel to the electron layers, the…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 O. N. Makarovskii , L. Smrcka , P. Vasek , T. Jungwirth , M. Cukr , L. Jansen

The spin susceptibility of a two-dimensional electron system is calculated by determining the spin-polarization dependence of the ground-state energy within the self-consistent mean-field theory of Singwi et al. (STLS). Results are…

Strongly Correlated Electrons · Physics 2011-06-03 R. K. Moudgil , Krishan Kumar , Gaetano Senatore

The spin polarization (P) of high-density InSb two-dimensional electron systems (2DESs) has been measured using both parallel and tilted magnetic fields. P is found to exhibit a superlinear increase with the total field B. This P-B…

Strongly Correlated Electrons · Physics 2011-08-18 K. F. Yang , H. W. Liu , T. D. Mishima , M. B. Santos , K. Nagase , Y. Hirayama