相关论文: Hopping Transport in Granular Superconductors
Transport of charge carriers can be controlled by doping through chemical and physical means. Unlike chemical doping, physical doping is carried out by a special technique through gate voltages in a field-effect transistor geometry. This…
We study the hopping transport of a quantum particle through finite, randomly diluted percolation clusters in two dimensions. We investigate how the transmission coefficient T behaves as a function of the energy E of the particle, the…
We build a microscopic model to study the intra- and inter-layer superexchange due to electrons hopping in chromium trihalides ($\mathrm{CrX}_3$, X= Cl, Br, and I). In evaluating the superexchange, we identify the relevant intermediate…
Cluster dynamical mean field methods are used to calculate the normal and anomalous components of the electron self energy of the two dimensional Hubbard model. From these the evolution of the superconducting gap and the momentum dependent…
We have studied the extended Hubbard model with pair hopping in the atomic limit for arbitrary electron density and chemical potential. The Hamiltonian considered consists of (i) the effective on-site interaction U and (ii) the intersite…
A qualitative model describing the "anomalous" features of the conductivity of polymer nanocomposites, in particular, switching to the conducting state in relatively thick (tens of microns or more) of flexible PVC films is considered. In…
Cosine-shaped bands that occur in DFT-based electronic band structures for MgB2 are further analyzed with calculations along reciprocal directions parallel to the high symmetry G-A direction at regular intervals along G-M. Band degeneracies…
We discuss the structure of the superconducting gap in iron pnictides. In the itinerant electron picture, gaps with or without nodes have the extended s-wave (s+) symmetry and emerge within the same pairing mechanism, determined by the…
Two experiments are described which are related to the problem of localized Cooper pairs. Magnetic-field-tuned superconductor-insulator transition was studied in amorphous In--O films with onset of the superconducting transition in zero…
We model a Superconducting Single-Electron Transistor operating by repulsive interactions. The device consists of a ring of Hubbard clusters, placed between electrodes and capacitively coupled to a gate potential. In each cluster, a pair of…
The emergence of superconductivity in unconventional superconductors usually accompanies the normal-state phases of pseudogap, strange metal and Fermi liquid. It indicates these phases are strongly related to the superconducting state and…
The electronic structure of the high-T_c cuprates is studied on the basis of both "large-U" and "small-U" orbitals. A striped structure is obtained, and three types of carriers: polaron-like "stripons" carrying charge, "quasielectrons''…
Transport properties of granular systems are governed by Coulomb blockade effects caused by the discreteness of the electron charge. We show that, in the limit of vanishing mean level spacing on the grains, the low-temperature behavior of…
Recent experiment on the tunneling spectra of ultrasmall superconducting grains revealed an unusual structure of the lowest differential conductance peak for grains in the odd charging states. We explain this behavior by nonequilibrium…
Spatially extended aggregates of dopants are ubiquitous in a plethora of granular superconductors, forming a droplet network that is very important to their characterization and to the description of their superconducting properties. At the…
We theoretically investigate the impact of correlated hopping on thermoelectric transport through a quantum dot coupled to ferromagnetic leads. Using the accurate numerical renormalization group method, we analyze the transport…
A simple model of cuprate superconductivity with an electron spectrum prepared by doping is developed. The pair-transfer interaction couples the itinerant band with two components ("hot'' and "cold'') of the defect subsystem. There are…
Experimental and theoretical studies on transport in semiconductor samples with superconducting electrodes are reported. We focus on the samples close to metal-insulator transition. In metallic samples, a peak of negative magnetoresistance…
We study the phase diagram of the Hubbard model in the weak-coupling limit for coexisting spin-density-wave order and spin-fluctuation-mediated superconductivity. Both longitudinal and transverse spin fluctuations contribute significantly…
We have investigated charge transport in ultrasmall superconducting single and double Josephson junctions coupled to resonant modes of the electromagnetic environment. We observe pronounced current peaks in the transport characteristics of…