16 research outputs found

    Coherent resistance of a disordered 1D wire: Expressions for all moments and evidence for non-Gaussian distribution

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    We study coherent electron transport in a one-dimensional wire with disorder modeled as a chain of randomly positioned scatterers. We derive analytical expressions for all statistical moments of the wire resistance ρ\rho. By means of these expressions we show analytically that the distribution P(f)P(f) of the variable f=ln(1+ρ)f=\ln(1+\rho) is not exactly Gaussian even in the limit of weak disorder. In a strict mathematical sense, this conclusion is found to hold not only for the distribution tails but also for the bulk of the distribution P(f)P(f).Comment: Revised version, 8 pages, 4 figures, RevTeX

    Complex Field Induced States in Linarite PbCuSO4 OH 2 with a Variety of High Order Exotic Spin Density Wave States

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    Low temperature neutron diffraction and NMR studies of field induced phases in linarite are presented for magnetic fields H amp; 8741;b axis. A two step spin flop transition is observed, as well as a transition transforming a helical magnetic ground state into an unusual magnetic phase with sine wave modulated moments amp; 8741; H. An effective J 1 amp; 8722;J 2 single chain model with a magnetization dependent frustration ratio amp; 945;ef f amp; 8722;J 2 J 1 is proposed. The latter is governed by skew interchain couplings and shifted to the vicinity of the ferromagnetic critical point. It explains qualitatively the observation of a rich variety of exotic longitudinal collinear spin density wave, SDWp, states 9 amp; 8805; p amp; 8805;

    Experimental determination of Rashba and Dresselhaus parameters and g*- factor anisotropy via Shubnikov-de Haas oscillations

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    The spin splitting of conduction band electrons in inversion-asymmetric InGaAs/InP quantum wells (QWs) is studied by Shubnikov-de Haas measurements combining the analysis of beating patterns and coincidence measurements in doubly tilted magnetic fields. The method allows us to determine the absolute values of the Rashba and linear Dresselhaus spin-orbit interaction (SOI) coefficients, their relative sign and the full Lande g-tensor. This is achieved by analyzing the anisotropy of the beat node positions with respect to both polar and azimuthal angles between the magnetic field direction and the QW normal. Weshow that the SOI is dominated by a large Rashba coefficient together with a linear Dresselhaus coefficient that is 10% of the Rashba coefficient. Their relative sign is found to be positive. The g-tensor is found to have a marked out-of-plane anisotropy and a smaller but distinct in-plane anisotropy due to SOI

    Spin-orbit coupling and phase coherence in InAs nanowires

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    We investigated the magnetotransport of InAs nanowires grown by selective-area metal-organic vapor phase epitaxy. In the temperature range between 0.5 and 30 K reproducible fluctuations in the conductance upon variation in the magnetic field or the backgate voltage are observed, which are attributed to electron interference effects in small disordered conductors. From the correlation field of the magnetoconductance fluctuations the phase-coherence length l(phi) is determined. At the lowest temperatures l(phi) is found to be at least 300 nm while for temperatures exceeding 2 K a monotonous decrease in l(phi) with temperature is observed. A direct observation of the weak antilocalization effect indicating the presence of spin-orbit coupling is masked by the strong magnetoconductance fluctuations. However, by averaging the magnetoconductance over a range of gate voltages a clear peak in the magnetoconductance due to the weak antilocalization effect was resolved. By comparison of the experimental data to simulations based on a recursive two-dimensional Green's-function approach a spin-orbit scattering length of approximately 70 nm was extracted, indicating the presence of strong spin-orbit coupling
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