Related papers: Two Gap State Density in MgB$_{2}$: A True Bulk Pr…
Single crystal of Lu$_2$Fe$_3$Si$_5$ was studied with the tunnel-diode resonator technique in Meissner and mixed states. Temperature dependence of the superfluid density provides strong evidence for the two-gap superconductivity with almost…
Using intrinsic multiple Andreev reflection effect (IMARE) spectroscopy we studied superconducting properties of nearly optimal oxygen-deficient GdFeAsO$_{0.88}$ polycrystalline samples (bulk critical temperatures $T_C^{bulk} = 49 \div…
The optical response of the two-band superconductor MgB$_2$ has been studied in the 0.7-4 THz range on films with very low impurity level. The effect of the high-energy $\sigma$-gap is observed in the ratio $R_S/R_N$ between the normal and…
We present thermal conductivity measurements on very pure and dense bulk samples, as indicated by residual resistivity values as low as 0.5 mW cm and thermal conductivity values higher than 200 W/mK. In the normal state we found that the…
We present the ultralow-temperature thermal conductivity measurements on single crystals of transition-metal dichalcogenide material 4Hb-TaS$_{2}$, which has recently been proposed as a topological superconductor candidate. In zero field, a…
The Andreev reflection measurements of the superconducting energy gap in the carbon-substituted MgB$_2$ are presented. Despite the strong suppression of the transition temperature by 17 K in comparison with the pure MgB$_2$, the same…
Starting from first principles, we show the formation and evolution of superconducting gaps in MgB$_2$ at its ultrathin limit. Atomically thin MgB$_2$ is distinctly different from bulk MgB$_2$ in that surface states become comparable in…
Based on a Fermi liquid picture, the temperature effect on the impurity-induced spatial modulation of local density of states (LDOS) is investigated for the d-wave superconductor Bi$_2$Sr$_2$CaCu$_2$O$_8$, in the context of scanning…
We investigate pseudogap phenomena originating from pairing fluctuations in the BCS-BEC crossover regime of a two-dimensional Fermi gas in a harmonic trap. Including pairing fluctuations within a $T$-matrix theory and effects of a trap…
The specific heat C of a sintered polycrystalline sample of MgB2 with a bulk superconducting transition temperature Tc=36.7 K is measured as a function of the temperature (2-300 K) and magnetic field (0-16 T), together with magnetic…
Multiband superconductivity arises when multiple electronic bands contribute to the formation of the superconducting state, allowing distinct pairing interactions and gap structures. Here, we present field- and temperature-dependent data on…
Several theoretical analyses of the two superconducting energy gaps of magnesium diboride, $\Delta_\pi$ and $\Delta_\sigma$, predict substructures within each energy gap, rather than two pure numbers. Recent experiments have revealed…
In this paper, potential two-gap superconductivity in Mo$_8$Ga$_{41}$ is addressed in detail by means of thermodynamic and spectroscopic measurements. Combination of highly sensitive ac-calorimetry and scanning tunneling spectroscopy (STS),…
We theoretically investigate excitation properties in the pseudogap regime of a trapped Fermi gas. Using a combined $T$-matrix theory with the local density approximation, we calculate strong-coupling corrections to single-particle local…
We use the tomographic density of states (TDoS), which is a measure of the density of states for a single slice through the band structure of a solid, to study the temperature evolution of the superconducting gap in the cuprates. The TDoS…
The recent discovery of superconductivity at ~39 K in MgB2, by Nagamatsu et al. establishes this simple binary compound as having the highest bulk superconducting transition temperature, Tc, of any non-copper-oxide material. Much of the…
We have experimentally investigated the density of states (DOS) in Nb/Ni (S/F) bilayers as a function of Ni thickness, $d_F$. Our thinnest samples show the usual DOS peak at $\pm\Delta_0$, whereas intermediate-thickness samples have an…
Measurements of the penetration depth $\lambda (T,H)$ in the presence of a DC magnetic field were performed in $MgB_2$ wires. In as-prepared wires $\lambda (T,H<130 Oe)$ shows a strong diamagnetic downturn below $\approx 10 K$. A DC…
Magnesium diboride MgB2 has been an extraordinarily hot research topic since the discovery of superconductivity below 40 K, due to the vast amount of unusual properties originating from the involvement in superconductivity of two sets of…
The optical conductivity of MgB$_2$ has been determined on a dense polycrystalline sample in the spectral range 6 meV - 4.6 eV using a combination of ellipsometric and normal incidence reflectivity measurements. $\sigma_{1}(\omega)$…