Related papers: AC Conductivity Crossover in Localized Superconduc…
The complex ac conductivity of thin highly disordered InOx films was studied as a function of magnetic field through the nominal two-dimensional superconductor-insulator transition. We have resolved a significant finite-frequency superfluid…
Localization and dephasing of conduction electrons in a low carrier density ferromagnet due to scattering on magnetic fluctuations is considered. We claim the existence of the "mobility edge", which separates the states with fast diffusion…
In 2007, type-I superconductivity in heavily boron-doped silicon carbide was discovered. The question arose, if it is possible to achieve a superconducting phase by introducing dopants different from boron. Recently, aluminum-doped silicon…
Low-temperature (T) heat-capacity measurements under hydrostatic pressure of up to p=2.1 GPa have been performed on single-crystalline CeCu2Si2. A broad superconducting (SC) region exists in the T-p phase diagram. In the low-pressure region…
Following our previous investigations on superconductivity in amorphous carbon (aC) based systems; we have prepared thin composite aC-W films using electron-beam induced deposition. The films did not show any sign for superconductivity…
The temperature dependencies of the excess conductivity $\sigma'(T)$ and possible pseudogap (PG), in a Dy$_{0.6}$Y$_{0.4}$Rh$_{3.85}$Ru$_{0.15}$B$_4$ polycrystal were studied for the first time. It was shown that $\sigma'(T)$ near T$_{c}$…
The characteristics of Fe-based superconductors are manifested in their electronic, magnetic properties, and pairing symmetry of the Cooper pair, but the latter remain to be explored. Usually in these materials, superconductivity coexists…
Weak localization leads to the same correction to both the conductivity and the electron-phonon coupling constant $\lambda$ (and $\lambda_{tr}$). Consequently the temperature dependence of the (thermal) electrical resistivity is decreasing…
Temperature-pressure ($T$-$P$) phase diagrams of FeSe$_{\rm 1-x}$S$_{\rm x}$ were investigated by the measurements of dc magnetization ($M$) and electrical resistivity ($\rho$) under pressure, using single crystal specimens with $x$=0.04,…
We present a theory for quasiparticle heat transport through superconducting weak links. The thermal conductance depends on the phase difference ($\phi$) of the superconducting leads. Branch conversion processes, low-energy Andreev bound…
We analyze here the fluctuation conductivity in the vicinity of the critical point in a 2D Josephson junction array shunted by an Ohmic resistor.We find that at the Gaussian level, the conductivity acquires a logarithmic dependence on…
We construct a holographic effective superconducting theory by considering a special gauge-axion higher derivative term. The gauge-axion coupling results in the transport behavior similar to the vortex response in the dual boundary field…
We investigate the magnetic and superconducting properties in electron-doped Li$_x$HfNCl. HfNCl is a band insulator that undergoes an insulator to superconductor transition upon doping at $x\approx0.13$. The persistence of the insulating…
We show that a simple gravitational theory can provide a holographically dual description of a superconductor. There is a critical temperature, below which a charged condensate forms via a second order phase transition and the (DC)…
To study a nonlocal electron transport in an aluminum superconducting quasi-one-dimensional structure, we measured negative nonlocal (local) direct current voltages in the structure in a magnetic field near the critical temperature. The…
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…
We describe a simple AC susceptometer built in-house that can be used to make high-resolution measurements of the magnetic susceptibility of high-temperature superconductors in an undergraduate physics lab. Our system, cooled using liquid…
One of the first finding concerning the superconducting (SC) density $n_{\rm sc}$ in cuprates was their small magnitudes that revealed the importance of phase fluctuations. More recently, measurements in a variety of overdoped cuprates…
Based on the $t-t'-U-V$ model with proper chosen parameters for describing the cuprate superconductors, it is found that near the optimal doping at low temperature ($T$), only the pure d-wave superconductivity ($d$SC) prevails and the…
We examine nonlocal conductivity in high-temperature superconductors from a phenomenological point of view. One wants to deduce the properties of the conductivity, especially its inherent length scales, from the transport data. Although…