106 research outputs found

    Quantum kinetic description of Coulomb effects in one-dimensional nano-transistors

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    In this article, we combine the modified electrostatics of a one-dimensional transistor structure with a quantum kinetic formulation of Coulomb interaction and nonequilibrium transport. A multi-configurational self-consistent Green's function approach is presented, accounting for fluctuating electron numbers. On this basis we provide a theory for the simulation of electronic transport and quantum charging effects in nano-transistors, such as gated carbon nanotube and whisker devices and one-dimensional CMOS transistors. Single-electron charging effects arise naturally as a consequence of the Coulomb repulsion within the channel

    Quantum confinement corrections to the capacitance of gated one-dimensional nanostructures

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    With the help of a multi-configurational Green's function approach we simulate single-electron Coulomb charging effects in gated ultimately scaled nanostructures which are beyond the scope of a selfconsistent mean-field description. From the simulated Coulomb-blockade characteristics we derive effective system capacitances and demonstrate how quantum confinement effects give rise to corrections. Such deviations are crucial for the interpretation of experimentally determined capacitances and the extraction of application-relevant system parameters

    On the "Mandelbrot set" for a pair of linear maps and complex Bernoulli convolutions

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    We consider the "Mandelbrot set" MM for pairs of complex linear maps, introduced by Barnsley and Harrington in 1985 and studied by Bousch, Bandt and others. It is defined as the set of parameters λ\lambda in the unit disk such that the attractor AλA_\lambda of the IFS {λz1,λz+1}\{\lambda z-1, \lambda z+1\} is connected. We show that a non-trivial portion of MM near the imaginary axis is contained in the closure of its interior (it is conjectured that all non-real points of MM are in the closure of the set of interior points of MM). Next we turn to the attractors AλA_\lambda themselves and to natural measures νλ\nu_\lambda supported on them. These measures are the complex analogs of much-studied infinite Bernoulli convolutions. Extending the results of Erd\"os and Garsia, we demonstrate how certain classes of complex algebraic integers give rise to singular and absolutely continuous measures νλ\nu_\lambda. Next we investigate the Hausdorff dimension and measure of AλA_\lambda, for λ\lambda in the set MM, for Lebesgue-a.e. λ\lambda. We also obtain partial results on the absolute continuity of νλ\nu_\lambda for a.e. λ\lambda of modulus greater than 1/2\sqrt{1/2}.Comment: 22 pages, 5 figure

    Multivariate p-dic L-function

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    We construct multivariate p-adic L-function in the p-adic number fild by using Washington method.Comment: 9 page

    Microscopic Surface Structure of Liquid Alkali Metals

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    We report an x-ray scattering study of the microscopic structure of the surface of a liquid alkali metal. The bulk liquid structure factor of the eutectic K67Na33 alloy is characteristic of an ideal mixture, and so shares the properties of an elemental liquid alkali metal. Analysis of off-specular diffuse scattering and specular x-ray reflectivity shows that the surface roughness of the K-Na alloy follows simple capillary wave behavior with a surface structure factor indicative of surface induced layering. Comparison of thelow-angle tail of the K67Na33 surface structure factor with the one measured for liquid Ga and In previously suggests that layering is less pronounced in alkali metals. Controlled exposure of the liquid to H2 and O2 gas does not affect the surface structure, indicating that oxide and hydride are not stable at the liquid surface under these experimental conditions.Comment: 12 pages, 3 figures, published in Phys. Rev.

    Optically controlled 2D tunnelling in GaAs delta-doped p-n junction

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    A new type of an optically controlled tunnelling process in a specially designed Esaki diode is investigated. The additional peak appears due to tunnelling of 2D electrons accumulated at ground state of delta doped layers embedded nearby the p-n junction into the valence band of the p⁺-contact. It is found that the voltage position of an additional resonant peak shifts to lower bias voltage with increasing both incident light intensity and temperature. Our experimental data and theoretical simulations show that this shift is a result of an electrical field redistribution in the region of the p-n junction caused by non-equilibrium carriers generated with optic or thermal excitation
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