Related papers: Orbital-dependent two-band superconductivity in Mg…
We report the first study of the optical conductivity of MgB2 covering the range of its superconducting energy gap. Terahertz time-domain spectroscopy is utilized to determine the complex, frequency-dependent conductivity of thin films. The…
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…
The surface resistance (Rs) and the real part (sigma_1) of the microwave complex conductivity of a ~380 nm-thick polycrystalline MgB2 film with the critical temperature (Tc) of 39.3 K were investigated at ~8.5 GHz as a function of…
We present a unifying picture of the magnetic in-plane anisotropies of two-dimensional superconductors based on transition metal dichalcogenides. The symmetry considerations are first applied to constrain the form of the conductivity…
The optical conductivity, $\sigma(\omega)$, of the two dimensional one-band Hubbard model is calculated at finite temperature using exact diagonalization techniques on finite clusters. The in-plane d.c. resistivity, $\rho_{ab}$, is also…
We present results of in field directional point contact spectroscopy (DPCS) study in the quaternary borocarbide superconductor YNi2B2C, which is characterized by a highly anisotropic superconducting gap function. For I||a, the…
The ab-plane thermal conductivity $\kappa$ of single-crystalline hexagonal MgB_2 has been measured as a function of magnetic field H with orientations both parallel and perpendicular to the c-axis and at temperatures between 0.5 and 300 K.…
Experimental support is found for the multiband model of the superconductivity in the recently discovered system MgB2 with the transition temperature Tc = 39 K. By means of Andreev reflection evidence is obtained for two distinct…
The two-gap structure in the superconducting state of MgB_2 gives rise to unusual thermodynamic properties which depart markedly from the isotropic single-band BCS model, both in their temperature- and field dependence. We report and…
Opticcal conductivity spectra $\sigma_1(\omega)$ of Nd2-xCexCuO4 thin films, measured by the reflectance-transmittance method (R-T method) which has been proposed to investigate far-infrared spectroscopy, are investigated based on the…
We propose a two band model for superconductivity. It turns out that the simplest nontrivial case considers solely interband scattering, and both bands can be modeled as symmetric (around the Fermi level) and flat, thus each band is…
A recent experiment by Ma and collaborators shows that the gap anisotropy in ${\rm Bi}_2 {\rm Sr}_2 {\rm Ca}_1 {\rm Cu}_2 {\rm O}_{8+x}$ is strongly temperature dependent. In particular, the superconducting gap along the $\Gamma - M$…
We report on the Andreev spectroscopy and specific heat of high-quality single crystals BaFe$_{1.9}$Ni$_{0.1}$As$_{2}$. The intrinsic multiple Andreev reflection spectroscopy reveals two anisotropic superconducting gaps $\Delta_L \approx…
We studied the voltage and temperature dependency of the dynamic conductance of normal metal-MgB2 junctions obtained either with the point-contact technique (with Au and Pt tips) or by making Ag-paint spots on the surface of high-quality…
We demonstrate the effect of bandstructure on the superconducting properties of Pb by calculating the strong-coupling features in the optical conductivity, $\sigma(\omega)$, due to the electron-phonon interaction. The importance of momentum…
We have measured the Raman spectra of polycrystalline MgB$_{2}$ from 25 {\cm} to 1200 {\cm}. When the temperature was decreased below the superconducting transition temperature $T_c$, we observed a superconductivity-induced redistribution…
2$H$-NbS$_2$ is a classic example of an anisotropic multi-band superconductor, with significant recent work focussing on the interesting responses seen when high magnetic fields are applied precisely parallel to the hexagonal niobium…
We present the results of directional point-contact measurements in MgB_2 single crystals, in magnetic fields up to 9 T parallel to the c axis. By fitting the conductance curves of our point contacts -- showing clear Andreev-reflection…
The magnetic penetration depth, $\lambda^{-2}(T)$, in the basal plane of a magnesium diboride (MgB$_2$) film was measured using a two-coil mutual inductance technique at 50 kHz. This film has $T_c\simeq 38$ K, $\Delta T_c \leq 1$ K, and…