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EN
Effect of the coherent backscattering of the conduction electrons in three-dimensional structurally disordered metals specified by the Ioffe-Regel criterion is considered within the framework of the Morgan-Howson-Šaub theory of localisation which is based on the generalised kinetic equation for the Wigner distribution function and effective medium approximation. A formula for the electrical resistivity including the weak localisation correction is expressed in terms of the dimensionless transport parameter k_{F}l. The asymptotic form of the formula is derived and discussed in the context of the diagrammatic approach.
EN
The spin-dependent electronic transport is investigated in a paramagnetic resonant tunnelling diode formed from Zn_{1 - x}Mn_{x}Se quantum well between two ZnBeSe barrier layers. The spin-dependent current-voltage characteristics have been obtained in the presence of magnetic fields by solving the quantum kinetic equation for the Wigner distribution function and the Poisson equation in the self-consistent procedure. We have obtained two distinct current peaks due to the giant Zeeman splitting of electronic levels in a qualitative agreement with experiment. We have shown that the sign of spin current polarization can be reversed by tuning the bias voltage. Moreover, we have found the bias voltage windows with a nearly constant polarization.
EN
The phase-space formulation of quantum mechanics based on the Wigner distribution function is applied to investigate the influence of the scattering processes on the electronic position-momentum correlations in the resonant-tunnelling nanosystem.
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EN
Using the computer simulations we have studied the spin conductance of the InAs nanowire with three all-around gates that generate two coupled quantum dots in the nanowire. We have assumed that the same constant voltage is applied to the outermost (left and right) gates and investigated the effect of the varying central-gate voltage (V_{G}) and axially directed magnetic field B on the spin currents. The calculated spin-up and spin-down conductances exhibit pronounced oscillations as functions of V_{G}. In certain intervals of V_{G}, both the spin conductances oscillate in antiphase, which can be applied to the spin-filter operation.
EN
The degree of electronic localization in disordered one-dimensional systems is discussed. The model is simplified to a set of Diracδ-like functions used for the potential in the Schrödinger equation and calculations are carried out for the ground state. The disorder of topological character is introduced by the random shifts of the potential peaks. For comparison, we also discuss two aperiodic systems of the potential peaks: Thue-Morse and Fibonacci sequences. The localization, both in the momentum and the real space, is analyzed for different disorder strengths and sizes of the system. We calculate the localization length, and additionally we express the localization effects in terms of the inverse participation function and also by means of the Husimi quasi-classical distribution function in the phase space of the electron (position, momentum) coordinate system. We present the influence of disorder generated by the random and aperiodic sequences of potential on the energy spectrum.
EN
Calculations of the quantum correction to the DC conductance of a cylindrical nanowire due to the quantum interference are presented. The real space Cooperon equation is solved for cylindrical geometry. Using this approach, it is shown that the quantum correction to the conductance in the weak localisation regime depends not only on the dephasing processes but also on geometrical parameters of the nanowire.
EN
The influence of the applied gate voltage on the coherent propagation of the conduction electrons through the InGaAs/InP core-multishell nanowires with the surrounding gate is considered. The solution of the three-dimensional Schrödinger equation within the effective mass approximation is found using the adiabatic method. The electrostatic potential distribution generated by the all-around gate is determined from the self-consistent procedure applied to the Schrödinger-Poisson problem. The Landauer-Büttiker formalism and quantum transmission boundary method are applied to calculate the transport properties of the considered nanosystem.
EN
The problem of spin-dependent transport of electrons through a metallic nanostructure is considered. The system consists of non-magnetic metal wire with two magnetic impurities and is connected to two ferromagnetic leads. The differential conductance is calculated by using the transfer matrix method. The spin polarization of the conductance is also obtained. It was found that this polarization is dependent on the spin configuration of magnetic impurities. This dependence can be controlled by the applied bias voltage.
EN
The non-classical distribution function formalism is used for studying the electron transport in a nanosystem. We calculated the current-voltage characteristics of a triple barrier one-dimensional nanostructure which is connected to three-dimensional (highly doped semiconductor) reservoirs by the ohmic contacts. We also estimated the peak-to-valley ratio for the considered nanostructure and discussed the effect of switching the bias from peak-to-valley and from valley-to-peak voltages.
EN
Calculations of the current-voltage characteristics of the core-multishell nanowires for different radii of the core and various thicknesses of the shells are presented. A role of the conducting core and shells in the coherent transport under the influence of the gate voltage is discussed.
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