1,042 research outputs found
Political and Media Discourses about Integrating Refugees in the UK
The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.This article addresses political and media discourses about integrating refugees in the UK in the context of the “refugee crisis”. A discursive psychological approach is presented as the best way to understand what talk about the concept is used to accomplish in these debates. A large corpus of political discussions (13 hours of debate featuring 146 politicians) and 960 newspaper articles from the UK were discourse analysed. The analysis identified five dilemmas about integration: Integration is positive and necessary, but challenging; Host communities are presented as welcoming, but there are limits to their capacity; Refugees are responsible for integration, but host communities need to provide support; Good refugees integrate, bad ones don't; Refugees are vulnerable and are skilled. All are used to warrant the inclusion or exclusion of refugees. The responsibility of western nations to support refugees is therefore contingent on the refugees behaving in specific ways
Critical properties of S=1/2 Heisenberg ladders in magnetic fields
The critical properties of the Heisenberg two-leg ladders are
investigated in a magnetic field. Combining the exact diagonalization method
and the finite-size-scaling analysis based on conformal field theory, we
calculate the critical exponents of spin correlation functions numerically. For
a strong interchain coupling, magnetization dependence of the critical
exponents shows characteristic behavior depending on the sign of the interchain
coupling. We also calculate the critical exponents for the Heisenberg
two-leg ladder with a diagonal interaction, which is thought as a model
Hamiltonian of the organic spin ladder compound
. Numerical results are compared with
experimental results of temperature dependence of the NMR relaxation rate
.Comment: REVTeX, 10 pages, 8 figures, accepted for Phys. Rev.
Diffuse transport and spin accumulation in a Rashba two-dimensional electron gas
The Rashba Hamiltonian describes the splitting of the conduction band as a
result of spin-orbit coupling in the presence of an asymmetric confinement
potential and is commonly used to model the electronic structure of confined
narrow-gap semiconductors. Due to the mixing of spin states some care has to be
exercised in the calculation of transport properties. We derive the diffusive
conductance tensor for a disordered two-dimensional electron gas with
spin-orbit interaction and show that the applied bias induces a spin
accumulation, but that the electric current is not spin-polarized.Comment: REVTeX4 format, 5 page
Theoretical analysis of the experiments on the double-spin-chain compound -- KCuCl
We have analyzed the experimental susceptibility data of KCuCl and found
that the data are well-explained by the double-spin-chain models with strong
antiferromagnetic dimerization. Large quantum Monte Carlo calculations were
performed for the first time in the spin systems with frustration. This was
made possible by removing the negative-sign problem with the use of the dimer
basis that has the spin-reversal symmetry. The numerical data agree with the
experimental data within 1% relative errors in the whole temperature region. We
also present a theoretical estimate for the dispersion relation and compare it
with the recent neutron-scattering experiment. Finally, the magnitude of each
interaction bond is predicted.Comment: 4 pages, REVTeX, 5 figures in eps-file
Ballistic spin-polarized transport and Rashba spin precession in semiconductor nanowires
We present numerical calculations of the ballistic spin-transport properties
of quasi-one-dimensional wires in the presence of the spin-orbit (Rashba)
interaction. A tight-binding analog of the Rashba Hamiltonian which models the
Rashba effect is used. By varying the robustness of the Rashba coupling and the
width of the wire, weak and strong coupling regimes are identified. Perfect
electron spin-modulation is found for the former regime, regardless of the
incident Fermi energy and mode number. In the latter however, the
spin-conductance has a strong energy dependence due to a nontrivial subband
intermixing induced by the strong Rashba coupling. This would imply a strong
suppression of the spin-modulation at higher temperatures and source-drain
voltages. The results may be of relevance for the implementation of
quasi-one-dimensional spin transistor devices.Comment: 19 pages (incl. 9 figures). To be published in PR
Observation of Field-Induced Transverse N\'{e}el Ordering in the Spin Gap System TlCuCl
Neutron elastic scattering experiments have been performed on the spin gap
system TlCuCl in magnetic fields parallel to the -axis. The magnetic
Bragg peaks which indicate the field-induced N\'{e}el ordering were observed
for magnetic field higher than the gap field T at with odd in the plane. The spin structure in the ordered
phase was determined. The temperature and field dependence of the Bragg peak
intensities and the phase boundary obtained were discussed in connection with a
recent theory which describes the field-induced N\'{e}el ordering as a
Bose-Einstein condensation of magnons.Comment: 4 pages, 5 eps figures, jpsj styl
The farmer and the cost of local rural government in Missouri
Cover title.Includes bibliographical references
Spin Hall effect transistor
Spin transistors and spin Hall effects have been two separate leading
directions of research in semiconductor spintronics which seeks new paradigms
for information processing technologies. We have brought the two directions
together to realize an all-semiconductor spin Hall effect transistor. Our
scheme circumvents semiconductor-ferromagnet interface problems of the original
Datta-Das spin transistor concept and demonstrates the utility of the spin Hall
effects in microelectronics. The devices use diffusive transport and operate
without electrical current, i.e., without Joule heating in the active part of
the transistor. We demonstrate a spin AND logic function in a semiconductor
channel with two gates. Our experimental study is complemented by numerical
Monte Carlo simulations of spin-diffusion through the transistor channel.Comment: 11 pages, 3 figure
Spin-polarized transport in inhomogeneous magnetic semiconductors: theory of magnetic/nonmagnetic p-n junctions
A theory of spin-polarized transport in inhomogeneous magnetic semiconductors
is developed and applied to magnetic/nonmagnetic p-n junctions. Several
phenomena with possible spintronic applications are predicted, including
spinvoltaic effect, spin valve effect, and giant magnetoresistance. It is
demonstrated that only nonequilibrium spin can be injected across the
space-charge region of a p-n junction, so that there is no spin injection (or
extraction) at low bias.Comment: Minor Revisions. To appear in Phys. Rev. Let
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