Related papers: AC Conductivity Crossover in Localized Superconduc…
High-quality KFe2As2 single crystals have been studied by transport, magnetization and low-T specific heat measurements. Their analysis shows that superconductivity occurs (in some cases coexists) in the vicinity of disordered magnetic…
Transport through a one-dimensional wire of interacting electrons connected to semi infinite leads is investigated using a bosonization approach. The dynamic nonlocal conductivity is rigorously expressed in terms of the transmission. For…
We study local moment formation in the presence of superconducting correlations among the f-electrons in the periodic Anderson model. Local moments form if the Coulomb interaction U>U_cr. We find that U_cr is considerably stronger in the…
We study Anderson localization in quasi--one--dimensional disordered wires within the framework of the replica $\sigma$--model. Applying a semiclassical approach (geodesic action plus Gaussian fluctuations) recently introduced within the…
We study the quasiparticle transport coefficients in disordered d-wave superconductors. We find that spin and charge excitations are generally localized unless magnetic impurities are present. If the system is close to a nesting point in…
We study Anderson localization in disordered helical conductors that are obtained from one-dimensional conductors with spin-orbit interaction and a magnetic field, or from equivalent systems. We call such conductors "quasi-helical" because…
The response of mesoscopic superconductors to an ac magnetic field is numerically investigated on the basis of the time-dependent Ginzburg-Landau equations (TDGL). We study the dependence with frequency $\omega$ and dc magnetic field…
When superconducting (SC) and charge-density wave (CDW) orders compete, novel low temperature behaviors can result. From an analysis of the Landau-Ginzberg-Wilson theory of competing orders, we demonstrate the generic occurrence of a…
Taking advantage of a novel multiprobe setup we have measured, on a unique sample, the ac-magnetic susceptibility, the resistivity, the ac-specific heat and the thermopower of the superconductor heavy fermion CeCu$_{2}$Si$_{2}$ under…
The dynamic spin susceptibility, $\chi''(\omega)$, has been measured over the energy range of $2 \leq \omega \leq 10$ meV for overdoped La$_{2-x}$Sr$_{x}$CuO$_{4}$. Incommensurate (IC) spin excitations are observed at 8 K for all…
For an electron density near the H=0 insulator-to-conductor transition, the magnetoconductivity of the low-temperature conducting phase in high-mobility silicon MOSFETs is consistent with the form…
The effect of disorder on the electronic properties near the Mott transition is studied in an organic superconductor $\kappa$-(BEDT-TTF)$_{2}$Cu[N(CN)$_{2}$]Br, which is systematically irradiated by X-ray. We observe that X-ray irradiation…
We study the statistics of the conductance $g$ through one-dimensional disordered systems where electron wavefunctions decay spatially as $|\psi| \sim \exp (-\lambda r^{\alpha})$ for $0 <\alpha <1$, $\lambda$ being a constant. In contrast…
The origin of AC resistivity in the high Tc superconductors is not addressed adequately in literature. We found out, Josephson Junction (JJ) decoupling is the main origin of the AC resistivity in high Tc superconductors. We have measured…
Low-temperature dissipation due to vortex motion in strongly anisotropic type-II superconductors with a moderate disorder ($\Delta^2/E_F \ll \hbar/\tau \ll \Delta$) is shown to be determined by the Zener-type transitions between the…
Characterizing superconducting microwave resonators with highly dissipative elements is a technical challenge, but a requirement for implementing and understanding the operation of hybrid quantum devices involving dissipative elements, e.g.…
The conductance coefficients of disordered mesoscopic devices with $n$ probes are investigated within the noninteracting electron approximation at zero temperature. The probes are eliminated from the theoretical description at the expense…
The AC conductivity response in a broad frequency range of disordered materials is of great interest not only for technological applications, but also from a theoretical point of view. The Jonscher power exponent value, and its temperature…
We show that recent measurements of the magnetic field dependence of the magnetization, specific heat and resistivity of overdoped $T_c \sim 17K$ $Tl_{2}Ba_{2}CuO_{6+\delta}$ in the vicinity of the superconducting $H_{c2}$ imply that the…
We propose a phenomenological Ginzburg-Landau-like theory of cuprate superconductivity. The free energy is expressed as a functional F of the spin-singlet pair amplitude psi_ij=psi_m=Delta_m exp(i phi_m); i and j are nearest-neighbor sites…