14,769 research outputs found

    Spin-current injection and detection in strongly correlated organic conductor

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    Spin-current injection into an organic semiconductor κ-(BEDT-TTF)2Cu[N(CN)2]Br\rm{\kappa\text{-}(BEDT\text{-}TTF)_2Cu[N(CN)_2]Br} film induced by the spin pumping from an yttrium iron garnet (YIG) film. When magnetization dynamics in the YIG film is excited by ferromagnetic or spin-wave resonance, a voltage signal was found to appear in the κ-(BEDT-TTF)2Cu[N(CN)2]Br\rm{\kappa\text{-}(BEDT\text{-}TTF)_2Cu[N(CN)_2]Br} film. Magnetic-field-angle dependence measurements indicate that the voltage signal is governed by the inverse spin Hall effect in κ-(BEDT-TTF)2Cu[N(CN)2]Br\rm{\kappa\text{-}(BEDT\text{-}TTF)_2Cu[N(CN)_2]Br}. We found that the voltage signal in the κ-(BEDT-TTF)2Cu[N(CN)2]Br\rm{\kappa\text{-}(BEDT\text{-}TTF)_2Cu[N(CN)_2]Br}/YIG system is critically suppressed around 80 K, around which magnetic and/or glass transitions occur, implying that the efficiency of the spin-current injection is suppressed by fluctuations which critically enhanced near the transitions

    Model anisotropic quantum Hall states

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    Model quantum Hall states including Laughlin, Moore-Read and Read-Rezayi states are generalized into appropriate anisotropic form. The generalized states are exact zero-energy eigenstates of corresponding anisotropic two- or multi-body Hamiltonians, and explicitly illustrate the existence of geometric degrees of in the fractional quantum Hall effect. These generalized model quantum Hall states can provide a good description of the quantum Hall system with anisotropic interactions. Some numeric results of these anisotropic quantum Hall states are also presented.Comment: 10 pages, 5 figure

    Far-infrared optical properties of the pyrochlore spin ice compound Dy2Ti2O4

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    Near normal incident far-infrared reflectivity spectra of [111] dysprosium titanate (Dy2Ti2O4) single crystal have been measured at different temperatures. Seven phonon modes (eight at low temperature) are identified at frequency below 1000 cm-1. Optical conductivity spectra are obtained by fitting all the reflectivity spectra with the factorized form of the dielectric function. Both the Born effective charges and the static optical primitivity are found to increase with decreasing temperature. Moreover, phonon linewidth narrowering and phonon modes shift with decreasing temperature are also observed, which may result from enhanced charge localization. The redshift of several low frequency modes is attributed to the spin-phonon coupling. All observed optical properties can be explained within the framework of nearest neighbor ferromagnetic(FM) spin ice model
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