相关论文: Quantum percolation in granular metals
A tunnelling conductivity between a heavy fermion metal and a simple metallic point is considered. We show that at low temperatures this conductivity can be noticeably dissymmetrical with respect to the change of voltage bias. The…
We investigate how temperature affects transport through large networks of nonlinear conductances with distributed thresholds. In monolayers of weakly-coupled gold nanocrystals, quenched charge disorder produces a range of local thresholds…
Disordered thin films close to the superconducting-insulating phase transition (SIT) hold the key to understanding quantum phase transition in strongly correlated materials. The SIT is governed by superconducting quantum fluctuations, which…
We consider interaction of an electron with a Bose condensate of atoms having electron affinity. Though states of the electron attached to atoms form a continuous band, tunneling through this band is strongly suppressed by quantum…
The Efros-Shklovskii law for the conductivity of granular metals is interpreted as a result of a variable range cotunneling process. The cotunneling between distant resonant grains is predominantly elastic at low T << T_c, while it is…
We studied phase coherent phenomena in mesoscopic Permalloy samples by exploring low temperature transport. Both, differential conductance as a function of bias voltage and magnetoconductance of individual wires display conductance…
Cluster-assembled metallic films show interesting electrical properties, both in the near-to-percolation regime, when deposited clusters do not form a complete layer yet, and when the film thickness is well above the electrical percolation…
We perform a detailed calculation of the various contributions to the fluctuation conductivity of a granular metal close to its superconducting transition. We find three distinct regions of power law behavior in reduced temperature,…
While classical percolation is well understood, percolation effects in randomly packed or jammed structures are much less explored. Here we investigate both experimentally and theoretically the electrical percolation in a binary composite…
The interplay between electron-electron interactions and weak localization (or anti-localization) phenomena in two-dimensional systems can significantly enhance the superconducting transition temperature. We develop the theory of quantum…
The ferromagnetic transition in a diluted magnetic semiconductor with localized charge carriers is inevitably a percolation transition. In this work we theoretically study the correlation between this magnetic percolation and transport…
An integer Quantum Hall effect transition is studied in a modulation doped p-SiGe sample. In contrast to most examples of such transitions the longitudinal and Hall conductivities at the critical point are close to 0.5 and 1.5 (e^2/h), the…
When charge current passes through a normal metal that exhibits spin Hall effect, spin accumulates at the edge of the sample in the transverse direction. We predict that this spin accumulation, or spin voltage, enables quantum tunneling of…
We present microscopic transport calculations of the tunneling spectra of non-magnetic metal nanoparticles. We show that charge fluctuations give rise to tunneling resonances of a new type. Positive and negative fluctuations have differing…
We study the electron thermal transport in granular metals at large tunnel conductance between the grains, $g_T \gg 1$ and not too low a temperature $T > g_T\delta$, where $\delta$ is the mean energy level spacing for a single grain. Taking…
We theoretically investigate quantum fluctuation of charge between even and odd states of a normal-superconducting-normal single-electron tunneling transistor. It is shown that due to the superconducting gap, the charge fluctuation in the…
The quantum Hall effect is studied numerically in modulated two-dimensional electron systems in the presence of disorder. Based on the scaling property of the Hall conductivity as well as the localization length, the critical energies where…
When a quantum many-particle system exists on a randomly diluted lattice, its intrinsic thermal and quantum fluctuations coexist with geometric fluctuations due to percolation. In this paper, we explore how the interplay of these…
We investigate the interference correction to the conductivity of a medium consisting of metallic grains connected by tunnel junctions. Tunneling conductance between the grains, $e^2g_{\rm T}/\pi\hbar$, is assumed to be large, $g_{\rm T}\gg…
Self-consistent theory of electron localization in disordered systems is generalized for the case of interacting electrons. We propose and critically compare a number of possible self-consistency schemes which take into account the lowest…