Anomalous Hall effect and weak localization corrections in a ferromagnet

In this paper, we report results on the anomalous Hall effect. First, we summarize analytical calculations based on the Kubo formalism : explicit expressions for both skew-scattering and side-jump are derived and weak-localization corrections are discussed. Next, we present numerical calculations of the anomalous Hall resistivity based on the Dirac equation. Qualitative agreement with experiments is obtained.Comment: Proceeding JEMS'0

Spin current in (110)-oriented GaAs quantum wells

We consider a possibility of generation of the stationary spin current in (110) – oriented GaAs-basedsymmetric quantum well due to the nonlinear response to externalperiodic electric field. The model includes the Dresselhaus spin-orbit interaction and the random Rashbaspin-orbit coupling. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2055

Current-in-plane magnetoresistance : a new approach to boundary conditions

We have rigorously calculated all the possible two-body rate constants associated with population dynamics of the hyperfine levels of atomic hydrogen as a function of magnetic field at T=0 K. These results are important in view of the recently suggested use of magnetic traps to obtain Bose-Einstein condensation

Ferromagnetic ordering in diluted magnetic semiconductors

We present a general approach to the problem of a ferromagnetic phase transition in diluted magnetic semiconductors. The Curie temperature of ferromagnetic transition is calculated in the mean field approximation. It is shown that the Curie temperature is determined by an integrated coupling between magnetic impurities.Запропоновано загальний підхід до проблеми феромагнітного фазового переходу в легованих магнітних напівпровідниках. Температуру Кюрі феромагнітного переходу обчислено в наближенні середнього поля. Показано, що температура Кюрі визначається через інтеграл від парної взаємодії між магнітними домішками

Piezoelectric effect in p -Si/SiGe/(001)Si modulation doped heterostructures

We present the results of calculations of the piezoelectric effect in a Si/SiGe multilayer structure with a narrow quantum well and a wide layer of doped Si semiconductor. The proposed theory is a possible explanation of some recent experiments on these structures.Представлені результати розрахунків п’єзоелектричного ефекту в Si/SiGe багатошаровій структурі з вузькою квантовою ямою і товстим шаром легованого напівпровідного кремнію Si. Запропонована теорія є можливим поясненням деяких недавніх екпериментів на цих структурах

Reflection of electrons from a domain wall in magnetic nanojunctions

Electronic transport through thin and laterally constrained domain walls in ferromagnetic nanojunctions is analyzed theoretically. The description is formulated in the basis of scattering states. The resistance of the domain wall is calculated in the regime of strong electron reflection from the wall. It is shown that the corresponding magnetoresistance can be large, which is in a qualitative agreement with recent experimental observations. We also calculate the spin current flowing through the wall and the spin polarization of electron gas due to reflections from the domain wall.Comment: 7 pages, 4 figure

Interlayer Exchange Coupling Mediated by Valence Band Electrons

The interlayer exchange coupling mediated by valence band electrons in all-semiconductor IV-VI magnetic/nonmagnetic superlattices is studied theoretically. A 3D tight-binding model, accounting for the band and magnetic structure of the constituent superlattice components is used to calculate the spin-dependent part of the total electronic energy. The antiferromagnetic coupling between ferromagnetic layers in EuS/PbS superlattices is obtained, in agreement with the experimental evidences. The results obtained for the coupling between antiferromagnetic layers in EuTe/PbTe superlattices are also presented.Comment: 8 pages, 6 figures, to be submitted to Phys.Rev.

Localization corrections to the anomalous Hall effect in a ferromagnet

We calculate the localization corrections to the anomalous Hall conductivity related to the contribution of spin-orbit scattering into the current vertex (side-jump mechanism). We show that in contrast to the ordinary Hall effect, there exists a nonvanishing localization correction to the anomalous Hall resistivity. The correction to the anomalous Hall conductivity vanishes in the case of side-jump mechanism, but is nonzero for the skew scattering. The total correction to the nondiagonal conductivity related to both mechanisms, does not compensate the correction to the diagonal conductivity.Comment: 7 pages with 7 figure

Twisted exchange interaction between localized spins embedded in a one- or two-dimensional electron gas with Rashba spin-orbit coupling

We study theoretically the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction in one- and two-dimensions in presence of a Rashba spin-orbit (SO) coupling. We show that rotation of the spin of conduction electrons due to SO coupling causes a twisted RKKY interaction between localized spins which consists of three different terms: Heisenberg, Dzyaloshinsky-Moriya, and Ising interactions. We also show that the effective spin Hamiltonian reduces to the usual RKKY interaction Hamiltonian in the twisted spin space where the spin quantization axis of one localized spin is rotated.Comment: 4pages, no figur

Edge scattering of electrons in graphene: Boltzmann equation approach to the transport in graphene nanoribbons and nanodisks

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