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Suppression of the critical temperature in homogeneously disordered superconducting films is a consequence of the disorder-induced enhancement of Coulomb repulsion. We demonstrate that for the majority of thin films studied now this effect cannot be completely explained under the assumption of two-dimensional diffusive nature of electron motion. The main contribution to the suppression of Tc arises from the correction to the electron-electron interaction constant coming from small scales of the order of the Fermi wavelength that leads to the critical temperature shift δTc/Tc0 ∼ − 1/kFl, where kF is the Fermi momentum and l is the mean free path. Thus almost for all superconducting films that follow the fermionic scenario of Tc suppression with decreasing the film thickness, this effect is caused by the proximity to the three-dimensional Anderson localization threshold and is controlled by the parameter kFl rather than the sheet resistance of the film. [ABSTRACT FROM AUTHOR]

The symmetry nature of the appearance of specific surface (edge) states at the boundaries of low-dimension structures with the symmetry of ribbons (borders) invariant with respect to time reversal is discussed. Symmetry reasons for the stability of such states against the elastic scattering from nonmagnetic impurities have been revealed. [ABSTRACT FROM AUTHOR]

Various regimes of Brownian motion of interacting (charged) dust particles in a plasma have been experimentally studied. A new analytical model for the correct description of the mass transfer dynamics of such particles, including the transition between the ballistic and diffusion regimes of their motion, has been proposed and experimentally tested. [ABSTRACT FROM AUTHOR]

We consider a mesoscopic ballistic structure with Rashba spin-orbit splitting of the electron spectrum. The ballistic region is attached to the leads with a voltage applied between them. We calculate the edge spin density which appears in the presence of a charge current through the structure due to the difference in populations of electrons coming from different leads. Combined effect of the boundary scattering and spin precession leads to oscillations of the edge polarization with the envelope function decaying as a power law of the distance from the boundary. The problem is solved with the use of scattering states. The simplicity of the method allows us gain an insight into the underlying physics. We clarify the role of the unitarity of scattering for the problem of edge spin accumulation. In case of a straight boundary it leads to exact cancellation of all long-wave oscillations of the spin density. As a result, only the Friedel-like spin density oscillations with the momentum 2 k survive. However, this appears to be rather exceptional case. In general, the smooth spin oscillations with the spin precession length recover, as it happens, e.g., for the wiggly boundary. We demonstrate also, that there is no relation between the spin current in the bulk, which is zero in the considered case, and the edge spin accumulation. [ABSTRACT FROM AUTHOR]

Dephasing in open quantum chaotic systems has been investigated in the limit of large system sizes to the Fermi wavelength ratio, L/λF 〉 1. The weak localization correction g wl to the conductance for a quantum dot coupled to (i) an external closed dot and (ii) a dephasing voltage probe is calculated in the semiclassical approximation. In addition to the universal algebraic suppression g wl ∝ (1 + τD/τϕ)−1 with the dwell time τD through the cavity and the dephasing rate τ, we find an exponential suppression of weak localization by a factor of ∝ exp[− $$\tilde \tau $$ /τϕ], where $$\tilde \tau $$ is the system-dependent parameter. In the dephasing probe model, $$\tilde \tau $$ coincides with the Ehrenfest time, $$\tilde \tau $$ ∝ ln[ L/λF], for both perfectly and partially transparent dot-lead couplings. In contrast, when dephasing occurs due to the coupling to an external dot, $$\tilde \tau $$ ∝ ln[ L/ξ] depends on the correlation length ξ of the coupling potential instead of λF. [ABSTRACT FROM AUTHOR]

The problem of the motion of an ensemble of classical particles in a periodic potential field has been considered. A method is proposed for generating directed ballistic transport by means of a perturbation oscillating in time and space. This method makes it possible to significantly reduce the perturbation intensity required to generate a particle flux. In particular, it has been shown that, even if the ensemble of particles is initially near the stable-equilibrium states, a directed flux appears at a perturbation amplitude of about 10−2 of the potential barrier height. The flux generation mechanism is associated with the creation of global chaotic diffusion due to resonances between spatial and time oscillations of perturbation. A nonlinear pendulum is considered as an example. [ABSTRACT FROM AUTHOR]

The ballistic conductance of a point contact between a strong ferromagnet and a d-wave superconductor is calculated for arbitrary spin-dependent transmission coefficients. The width of the localized Andreev state level is determined. The possibility of identifying the d-type superconductor by the shape of the voltage dependence of the conductance is analyzed for a point contact with a good metallic conduction. © 2005 Pleiades Publishing, Inc. [ABSTRACT FROM AUTHOR]

An experimental study of the two-, three-, and four-terminal resistance of a ballistic wire is carried out. The wire is fabricated on the basis of high-mobility 2D electron gas in an AlGaAs/GaAs heterojunction. Different behavior of mesoscopic fluctuations of multiterminal resistances is observed depending on the gate voltage and magnetic field. At B = 0.45 T, the four-terminal resistance drops almost to zero and features resembling a ballistic conductance quantization are observed. © 2004 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]