Related papers: Zero bias anomaly in a two dimensional granular in…
The electronic density of states (DOS) of La$_{0.625}$Ca$_{0.375}$MnO$_3$(LCMO) strain free epitaxial thin films with an insulator-metal transition temperature (T$_{IM}$) of 250 K was probed using variable temperature scanning tunneling…
We study charge transport in a granular array with high inter-grain conductances. We show that the system exhibits a Berezinskii-Kosterlitz-Thouless crossover from the high-temperature conducting state into a low-temperature insulating…
Strongly disordered superconductors in a magnetic field display many characteristic properties of type-II superconductivity--- except at low temperatures where an anomalous linear $T$-dependence of the resistive critical field $B_{c2}$ is…
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 investigated the local electronic density of states in superconductor-normal metal (Nb-Au) bilayers using a very low temperature (60 mK) STM. High resolution tunneling spectra measured on the normal metal (Au) surface show a clear…
We study the effect of superconducting fluctuations on the tunnel current-voltage characteristics of disordered superconducting films placed in a perpendicular magnetic field, $H$, in the whole $H$-$T$ phase diagram outside the…
It is shown that the Coulomb drag between two identical layers in the Anderson insulting state indicates a striking difference between the Mott and Efros-Shklovskii (ES) insulators. In the former, the trans-resistance $\rho_t$ is…
The disorder-induced Superconductor-to-Insulator Transition in amorphous Nb$_{x}$Si$_{1-x}$ two-dimensional thin films is studied for different niobium compositions $x$ through a variation of the sample thickness $d$. We show that the…
We study numerically the superconductor-insulator transition in two-dimensional inhomogeneous superconductors with gauge disorder, described by four different quantum rotor models: a gauge glass, a flux glass, a binary phase glass and a…
We show how the two-dimensional (2D) topological insulator evolves, by stacking, into a strong or weak topological insulator with different topological indices, proposing a new conjecture that goes beyond an intuitive picture of the…
We analyze cotunneling transport through two quantum dots in series weakly coupled to external ferromagnetic leads. In the Coulomb blockade regime the electric current flows due to third-order tunneling, while the second-order…
We calculate the low-energy tunneling density of states $\nu(\epsilon, T)$ of an $N$-channel disordered wire, taking into account the electron-electron interaction non-perturbatively. The finite scattering rate $1/\tau$ results in a…
Epitaxial thin films of charge-ordered Pr$_{0.625}$Ca$_{0.375}$MnO$_{3}$ have been studied using variable temperature Scanning tunneling microscopy and spectroscopy (STM/STS). The as grown films were found to be granular while the annealed…
The conductivity of a granular metal or an array of quantum dots usually has the temperature dependence associated with variable range hopping within the soft Coulomb gap of density of states. This is difficult to explain because neutral…
Since the prediction of spin-gapless semiconducting behaviour in the Heusler compound Mn$_2$CoAl, evidence of spin-gapless behaviour in thin films has typically been inferred from magnetotransport measurements. The spin gapless state is…
The Ising chain in transverse field is a paradigmatic model for a host of physical phenomena, including spontaneous symmetry breaking, topological defects, quantum criticality, and duality. Although the quasi-1D ferromagnet CoNb$_2$O$_6$…
Quantum transport measurements including the Altshuler-Aronov-Spivak (AAS) and Aharonov-Bohm (AB) effects, universal conductance fluctuations (UCF), and weak anti-localization (WAL) have been carried out on epitaxial Bi thin films ($10-70$…
We study the electronic densities of states (DOS) of strongly disordered superconducting thin films of TiN. We find, using Scanning Tunneling Microscopy (STM) that the DOS decreases towards the Fermi level in the normal phase obtained by…
We systematically investigated the temperature behaviors of the electrical conductivity and Hall coefficient of two series of amorphous indium gallium zinc oxides (a-IGZO) films prepared by rf sputtering method. The two series of films are…
Disordered thin films are a common choice of material for superconducting, high impedance circuits used in quantum information or particle detector physics. A wide selection of materials with different levels of granularity are available,…