1,038 research outputs found

    Political and Media Discourses about Integrating Refugees in the UK

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    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

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    The critical properties of the S=1/2S=1/2 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 S=1/2S=1/2 Heisenberg two-leg ladder with a diagonal interaction, which is thought as a model Hamiltonian of the organic spin ladder compound Cu2(1,4diazacycloheptane)2Cl4{Cu}_2({1,4-diazacycloheptane})_2{Cl}_4. Numerical results are compared with experimental results of temperature dependence of the NMR relaxation rate 1/T11/T_1.Comment: REVTeX, 10 pages, 8 figures, accepted for Phys. Rev.

    Diffuse transport and spin accumulation in a Rashba two-dimensional electron gas

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    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 -- KCuCl3_3

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    We have analyzed the experimental susceptibility data of KCuCl3_3 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

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    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 TlCuCl3_3

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    Neutron elastic scattering experiments have been performed on the spin gap system TlCuCl3_3 in magnetic fields parallel to the bb-axis. The magnetic Bragg peaks which indicate the field-induced N\'{e}el ordering were observed for magnetic field higher than the gap field Hg5.5H_{\rm g}\approx 5.5 T at Q=(h,0,l)Q=(h, 0, l) with odd ll in the aca^*-c^* 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

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    Cover title.Includes bibliographical references

    Spin Hall effect transistor

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    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

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    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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