188 research outputs found

    In-Plane Magnetolumnescence of Modulation-Doped GaAs/AlGaAs Coupled Double Quantum Wells

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    In-plane magnetic field photoluminescence spectra from a series of GaAs/AlGaAs coupled double quantum wells show distinctive doublet structures related to the symmetric and antisymmetric states. The magnetic field behavior of the upper transition from the antisymmetric state strongly depends on sample mobility. In lower mobility samples, the transition energy shows an N\cal N-type kink with fields (namely a maximum followed by a minimum), whereas higher mobility samples have a linear dependence. The former is due to a homogeneous broadening of electron and hole states and the results are in good agreement with theoretical calculations.Comment: 3 pages, 4 figures, submitted to Appl. Phys. Let

    Photoluminescence Detected Doublet Structure in the Integer and Fractional Quantum Hall Regime

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    We present here the results of polarized magneto-photoluminescence measurements on a high mobility single-heterojunction. The presence of a doublet structure over a large magnetic field range (2>nu>1/6) is interpreted as possible evidence for the existence of a magneto-roton minima of the charged density waves. This is understood as an indication of strong electronic correlation even in the case of the IQHE limit.Comment: submitted to Solid State Communication

    Multiskilling and Firm Performance

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    In this study, we examined uncertainty factors and human resource management practices that foster multiskilling of the workforce and the effect of multiskilling on labor productivity growth of the firm. An empirical analysis of 206 Korean manufacturing firms in 22 three-digit KSIC's showed the following results. First two uncertainty factors, the product demand variability in the industry and the occurrence of abnormal situations at the workplace, were positively associated with multiskill formation in the sample firms. Second, Human resource management practices such as mutual learning among coworkers, delegation of authority, and interworkshop mobility were positively associated with multiskill formation. Third, the degree of multiskill formation was positively associated with the firm's labor productivity growth from 1988 to 1993. Fourth, uncertainty had an indirect impact on labor productivity growth only through multiskill formation. When both uncertainty and multiskilling were included in the regression models, uncertainty had no impact on labor productivity growth. Fifth, we found growth effect of multiskilling but no level effect after controlling other factors