Electric readout of magnetization dynamics in a ferromagnet-semiconductor system

We apply an analysis of time-dependent spin-polarized current in a semiconductor channel at room temperature to establish how the magnetization configuration and dynamics of three ferromagnetic terminals, two of them biased and third connected to a capacitor, affect the currents and voltages. In a steady state, the voltage on the capacitor is related to spin accumulation in the channel. When the magnetization of one of the terminals is rotated, a transient current is triggered. This effect can be used for electrical detection of magnetization reversal dynamics of an electrode or for dynamical readout of the alignment of two magnetic contacts.Comment: Revised version, 8 pages, 3 figure

Spintronics for electrical measurement of light polarization

The helicity of a circularly polarized light beam may be determined by the spin direction of photo-excited electrons in a III-V semiconductor. We present a theoretical demonstration how the direction of the ensuing electron spin polarization may be determined by electrical means of two ferromagnet/semiconductor Schottky barriers. The proposed scheme allows for time-resolved detection of spin accumulation in small structures and may have a device application.Comment: Revised version, 8 two-column pages, 5 figures; Added: a comprehensive time dependent analysis, figures 3b-3c & 5, equations 6 & 13-16 and 3 references. submitted to Phys. Rev.

Role of Nucleophiles in Schiff Base Interaction with Nickel Ions

855-85

Quasiparticle Band Structure and Density Functional Theory: Single-Particle Excitations and Band Gaps in Lattice Models

We compare the quasiparticle band structure for a model insulator obtained from the fluctuation exchange approximation (FEA) with the eigenvalues of the corresponding density functional theory (DFT) and local density approximation (LDA). The discontinuity in the exchange-correlation potential for this model is small and the FEA and DFT band structures are in good agreement. In contrast to conventional wisdom, the LDA for this model overestimates the size of the band gap. We argue that this is a consequence of an FEA self-energy that is strongly frequency dependent, but essentially local.Comment: 8 pages, and 5 figure

Density-relaxation part of the self energy

A comment is made on the large-cluster limit of the self-energy correction for the quasiparticle energy gap in silicon clusters presented by Serdar Ogut, James R. Chelikowsky and Steven G. Louie in Phys. Rev. Lett. 79, 1770 (1997)

High temperature thermal conductivity of 2-leg spin-1/2 ladders

Based on numerical simulations, a study of the high temperature, finite frequency, thermal conductivity $\kappa(\omega)$ of spin-1/2 ladders is presented. The exact diagonalization and a novel Lanczos technique are employed.The conductivity spectra, analyzed as a function of rung coupling, point to a non-diverging $dc-$limit but to an unconventional low frequency behavior. The results are discussed with perspective recent experiments indicating a significant magnetic contribution to the energy transport in quasi-one dimensional compounds.Comment: 4 pages, 4 figure

Statistical Description in the Turbulent Near Wake of a Rotating Circular Cylinder

Turbulence studies were made in the wake of a rotating circular cylinder in a uniform free stream. The interest was to examine the turbulence properties at the suppression of periodicity in vortex formation process. An experimental study of the turbulent near wake of a rotating circular cylinder was made at a Reynolds number of 9000 for velocity ratios, λ between 0 and 2.7. Hot-wire anemometry and particle image velocimetry results indicate that the rotation of the cylinder causes significant changes in the vortical activities. The turbulence quantities are getting smaller as λ increases due to suppression of coherent vortex structures

Causal Relationship Between Oral Performance and Communication Apprehension

This study investigates the causal relationship between the form students who have passed in School-Based Oral Evaluation (SBOE) with communication apprehension. The participants are 302 of form four male and female students from the government secondary schools in Putrajaya Federal Territory, Malaysia. The purpose of this study is to determine the effectiveness of SBOE and its relationship with communication apprehension. This study is an explanatory sequential mixed method design in which quantitative and qualitative [11] data were collected in sequential, analyzed separately, and then explained. The quantitative data were collected by using FLCAS, SBOE results and the qualitative data were collected from the semi-structured interviews with the English teachers. The quantitative data were analysed by descriptive analysis (SPSS) and the qualitative data were analysed by content analysis. The results revealed that the students had scored high results in SBOE in the mid-term examination 2017. The findings from the quantitative and qualitative methods showed that students experience low level of communication apprehension. High oral performance affects communication apprehension. This study recommends a new oral-based English curriculum for the secondary schools.   Keywords: causal relationship, oral performance, language anxiety, communication apprehension, male and female students

Many-body diagrammatic expansion in a Kohn-Sham basis: implications for Time-Dependent Density Functional Theory of excited states

We formulate diagrammatic rules for many-body perturbation theory which uses Kohn-Sham (KS) Green's functions as basic propagators. The diagram technique allows to study the properties of the dynamic nonlocal exchange-correlation (xc) kernel $f_{xc}$. We show that the spatial non-locality of $f_{xc}$ is strongly frequency-dependent. In particular, in extended systems the non-locality range diverges at the excitation energies. This divergency is related to the discontinuity of the xc potential.Comment: 4 RevTeX pages including 3 eps figures, submitted to Phys. Rev. Lett; revised version with new reference

Eigenvalue spectrum for single particle in a spheroidal cavity: A Semiclassical approach

Following the semiclassical formalism of Strutinsky et al., we have obtained the complete eigenvalue spectrum for a particle enclosed in an infinitely high spheroidal cavity. Our spheroidal trace formula also reproduces the results of a spherical billiard in the limit $\eta\to1.0$. Inclusion of repetition of each family of the orbits with reference to the largest one significantly improves the eigenvalues of sphere and an exact comparison with the quantum mechanical results is observed upto the second decimal place for $kR_{0}\geq{7}$. The contributions of the equatorial, the planar (in the axis of symmetry plane) and the non-planar(3-Dimensional) orbits are obtained from the same trace formula by using the appropriate conditions. The resulting eigenvalues compare very well with the quantum mechanical eigenvalues at normal deformation. It is interesting that the partial sum of equatorial orbits leads to eigenvalues with maximum angular momentum projection, while the summing of planar orbits leads to eigenvalues with $L_z=0$ except for L=1. The remaining quantum mechanical eigenvalues are observed to arise from the 3-dimensional(3D) orbits. Very few spurious eigenvalues arise in these partial sums. This result establishes the important role of 3D orbits even at normal deformations.Comment: 17 pages, 7 ps figure