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We study a holographic model realizing an "antiferromagnetic" phase in which a global SU(2) symmetry representing spin is broken down to a U(1) by the presence of a finite electric charge density. This involves the condensation of a neutral…

High Energy Physics - Theory · Physics 2014-11-20 Nabil Iqbal , Hong Liu , Márk Mezei , Qimiao Si

We predict that a novel bias-voltage assisted magnetization reversal process will occur in Mn doped II-VI semiconductor quantum wells or heterojunctions with carrier induced ferromagnetism. The effect is due to strong exchange-coupling…

Materials Science · Physics 2009-11-07 Byounghak Lee , T. Jungwirth , A. H. MacDonald

We consider electron tunneling from a nonmagnetic $n$-type semiconductor ($n$-S) into a ferromagnet (FM) through a very thin forward-biased Schottky barrier resulting in efficient extraction of electron spin from a thin $n$-S layer near…

Materials Science · Physics 2009-11-10 A. M. Bratkovsky , V. V. Osipov

We study a simple microscopic model for thin, ferromagnetic, metallic layers on semi-infinite bulk superconductor. We find that for certain values of the exchange spliting, on the ferromagnetic side, the ground states of such structures…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 M. Krawiec , B. L. Gyorffy , J. F. Annett

The Helmholtz free energy F of the interacting 2-D electron fluid is calculated nonperturbatively using a mapping of the quantum fluid to a classical Coulomb fluid [Phys. Rev. Letters, vol. 87, 206404 (2001)]. For density parameters rs such…

Strongly Correlated Electrons · Physics 2009-11-07 M. W. C. Dharma-wardana , François Perrot

We study the thermodynamic phases of a gas of spin-1/2 atoms in the Hartree-Fock approximation. Our main result is that, for repulsive or weakly-attractive inter-component interaction strength, the superfluid and ferromagnetic phase…

Soft Condensed Matter · Physics 2009-11-10 S. Ashhab

We experimentally investigate spin-polarized electron transport between two ferromagnetic contacts, placed at the edge of a two-dimensional electron system with band inversion. The system is realized in a narrow (8~nm) HgTe quantum well,…

Mesoscale and Nanoscale Physics · Physics 2015-11-09 A. Kononov , S. V. Egorov , Z. D. Kvon , N. N. Mikhailov , S. A. Dvoretsky , E. V. Deviatov

To establish a correlation between the spin diffusion, the spin lifetime, and the electron density, we study, employing time-resolved magneto-optical Kerr effect microscopy, the spin polarization evolution in low-dimensional GaAs…

Mesoscale and Nanoscale Physics · Physics 2022-08-17 S. Anghel , A. V. Poshakinskiy , K. Schiller , G. Yusa , T. Mano , T. Noda , M. Betz

Critical phenomena of ferromagnetic transition at finite temperatures are studied in double-exchange systems. In order to investigate strong interplay between charge and spin degrees of freedom, Monte Carlo technique is applied to include…

Strongly Correlated Electrons · Physics 2009-11-07 Yukitoshi Motome , Nobuo Furukawa

We address the possible occurrence of ultracold atom ferromagnetism by evaluating the free energy of a spin polarized Fermi gas to second order in its interaction parameter. We find that Hartree-Fock theory underestimates the tendency…

Statistical Mechanics · Physics 2009-11-11 R. A. Duine , A. H. MacDonald

We have used quantum Monte Carlo methods to calculate the zero-temperature phase diagram of the two-dimensional homogeneous electron gas. We find a transition from a paramagnetic fluid to an antiferromagnetic triangular Wigner crystal at…

Mesoscale and Nanoscale Physics · Physics 2010-03-02 N. D. Drummond , R. J. Needs

We have performed a Quantum Monte Carlo study of a two-dimensional bulk sample of interacting 1/2-spin structureless fermions, a model of $^3$He adsorbed on a variety of preplated graphite substrates. We have computed the equation of state…

Statistical Mechanics · Physics 2015-05-27 M. Nava , E. Vitali , A. Motta , D. E. Galli , S. Moroni

The parallel field of a full spin polarization of the electron gas in a \Gamma8 conduction band of the HgTe quantum well was obtained from the magnetoresistance by three different ways in a zero and quasi-classical range of perpendicular…

Mesoscale and Nanoscale Physics · Physics 2015-05-28 M. V. Yakunin , A. V. Suslov , S. M. Podgornykh , S. A. Dvoretsky , N. N. Mikhailov

We show that suitably-designed magnetic semiconductor heterostructures consisting of Mn delta-doped GaAs and p-type AlGaAs layers, in which the locally high concentration of magnetic moments of Mn atoms are controllably overlapped with the…

Materials Science · Physics 2009-11-11 A. M. Nazmul , T. Amemiya , Y. Shuto , S. Sugahara , M. Tanaka

We use time-resolved Kerr rotation to demonstrate the optical and electronic tuning of both the electronic and local moment (Mn) spin dynamics in electrically gated parabolic quantum wells derived from II-VI diluted magnetic semiconductors.…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 R. C. Myers , K. C. Ku , X. Li , N. Samarth , D. D. Awschalom

Using real-time charge sensing and gate pulsing techniques we measure the ratio of the rates for tunneling into the excited and ground spin states of a single-electron AlGaAs/GaAs quantum dot in a parallel magnetic field. We find that the…

Mesoscale and Nanoscale Physics · Physics 2012-04-06 S. Amasha , K. MacLean , Iuliana P. Radu , D. M. Zumbuhl , M. A. Kastner , M. P. Hanson , A. C. Gossard

We present results of a combined density functional and many-body calculations for the electronic and magnetic properties of the defect-free digital ferromagnetic heterostructures obtained by doping GaAs with Cr and Mn. While local density…

Materials Science · Physics 2016-08-14 F. Beiuşeanu , C. Horea , E. -V. Macocian , T. Jurcuţ , L. Vitos , L. Chioncel

The interplay of tunneling transport and carrier-mediated ferromagnetism in narrow semiconductor multi-quantum well structures containing layers of GaMnAs is investigated within a self-consistent Green's function approach, accounting for…

Mesoscale and Nanoscale Physics · Physics 2015-05-27 Christian Ertler , Walter Pötz

We examine the robustness of a recently predicted exchange-induced zero-field magnetic phase in semiconductor double quantum wells in which each well is spin-polarized and the polarization vectors are antiparallel. Magnetic instabilities…

Mesoscale and Nanoscale Physics · Physics 2009-10-30 R. J. Radtke , S. Das Sarma , A. H. MacDonald

We consider low temperature transport through a lateral quantum dot asymmetrically coupled to two conducting leads, and tuned to the mixed-valence region separating two adjacent Coulomb blockade valleys with spin S=1/2 and S=1 on the dot.…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 M. Pustilnik , L. Borda
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