Related papers: Low temperature transport in granular metals
We describe electron transport through small metallic grains with Coulomb blockade effects beyond the perturbative regime. For this purpose we study the real-time evolution of the reduced density matrix of the system. In the first part of…
We have varied the disorder in a two-dimensional electron system in silicon by applying substrate bias. When the disorder becomes sufficiently low, we observe the emergence of the metallic phase, and find evidence for a metal-insulator…
We investigate thermopower and thermoelectric coefficient of nano-granular materials at large tunneling conductance between the grains, g_{T} >> 1. We show that at intermediate temperatures, T >= g_{T}\delta, where \delta is the mean energy…
In this work we present a detailed study and derivation of the thermopower and thermoelectric coefficient of nano-granular metals at large tunneling conductance between the grains, g_T>> 1. An important criterion for the performance of a…
We have measured the Hall coefficient $R_H$ and the electrical conductivity $\sigma$ of a series of ultrathin indium tin oxide films between 2 and 300 K. A robust $R_H$\,$\propto$\,ln$T$ law is observed in a considerably wide temperature…
The conductivity of extremely high mobility dilute two-dimensional holes in GaAs changes linearly with temperature in the insulating side of the metal-insulator transition. Hopping conduction, characterized by an exponentially decreasing…
Universality of the extraordinary Hall effect scaling was tested in granular three-dimensional Ni-SiO2 films across the metal-insulator transition. Three types of magnetotransport behavior have been identified: metallic, weakly insulating…
The non-equilibrium tunnel transport processes are considered in a square lattice of metallic nanogranules embedded into insulating host. Based on a simple model with three possible charging states (+,-, or 0) of a granule and three kinetic…
We investigate the effect of Coulomb interactions on the tunneling density of states (DOS) of granular metallic systems at the onset of Coulomb blockade regime in two and three dimensions. Using the renormalization group technique we derive…
Theory of quantum corrections to conductivity of granular metal films is developed for the realistic case of large randomly distributed tunnel conductances. Quantum fluctuations of intergrain voltages (at energies E much below bare charging…
We report direct experimental evidence that the insulating phase of a disordered, yet strongly interacting two-dimensional electron system (2DES) becomes unstable at low temperatures. As the temperature decreases, a transition from…
We have systematically investigated the electrical transport properties of polycrystalline TaN$_x$ ($0.83$$\lesssim$$x$$\lesssim$1.32) films with rocksalt structure from 300 down to 2 K. It is found that the conductivity varies linearly…
We have studied the metallic behaviour in low density GaAs hole systems, and Si electron systems, close to the apparent two-dimensional metal-insulator transition. Two observations suggest a semi-classical origin for the metallic-like…
We present a unified description of the low temperature phase of granular metals that reveals a striking generality of the low temperature behaviors. Our model explains the universality of the low-temperature conductivity that coincides…
Nanogranular metal composites, consisting of immiscible metallic and insulating phases deposited on a substrate, are characterized by two distinct electronic transport regimes depending on the relative amount of the metallic phase. At…
We calculate the junction resistance for a metal-barrier-metal device with the barrier tuned to lie just on the insulating side of the metal-insulator transition. We find that the crossover from tunneling behavior in thin barriers at low…
We have studied the temperature dependence of conductivity, $\sigma(T)$, in two series of Ag$_{x}$(SnO$_2$)$_{1-x}$ and Mo$_{x}$(SnO$_2$)$_{1-x}$ granular films lying below the percolation threshold, where $x$ is the metal volume fraction.…
The low-temperature conductivity of low-density, high-mobility, two-dimensional hole systems in GaAs was studied. We explicitly show that the metal-insulator transition, observed in these systems, is characterized by a well-defined critical…
We report in this Letter our recent low temperature transport results in a Si/SiGe quantum well with moderate peak mobility. An apparent metal-insulating transition is observed. Within a small range of densities near the transition, the…
We investigate the electrical and magneto-transport properties of Pt-C granular metals prepared by focused-electron-beam induced deposition. In particular, we consider samples close to the metal-insulator-transition obtained from as-grown…