Related papers: Surface effects in multiband superconductors. Appl…
A possible explanation is given for the anomalous $T^{3/2}$ temperature dependence of the electrical resistivity of MnSi, which is observed in the high-pressure paramagnetic state. The unusual Fermi surface of MnSi includes large open…
We report measurements on MgB2 up to ~40GPa. Increasing pressure yields a monotonous decrease of the lattice parameters and of the c/a ratio, but no structural transition down to parameters smaller than those of AlB2. The transition…
Multiband superconductors can host collective excitations with marked differences with respect to their single-band counterpart. We first study the spectrum of collective amplitude fluctuations in a clean two-bands superconductor, showing…
We report results of dc magnetic and ac linear low-frequency study of a polycrystalline MgB$_2$ sample. AC susceptibility measurements at low frequencies, performed under dc fields parallel to the sample surface, provide a clear evidence…
We study the single-particle spectral properties of electrons coupled to quasicritical charge and spin fluctuations close to a stripe-phase, which is governed by a Quantum Critical Point near optimum doping. We find that spectral weight is…
We present detailed studies of the high-field magnetoresistance of the layered organic metal $\kappa$-(BETS)$_2$\-Mn\-[N(CN)$_2$]$_3$ under a pressure slightly above the insulator-metal transition. The experimental data are analysed in…
We present a numerical study of conductance oscillations of transition metal multilayers as a function of layer thickness. Using a material-specific tight-binding model, we show that for disorder-free layers with random thicknesses but…
To reveal the relative importance of charge doping and defect scattering in substitutionally modified 122 iron pnictides, we perform a systematic first principles study on selected bands at the Fermi level. Disorder effects are induced by…
We have investigated the in-gap bound states (IGBS) induced by a single nonmagnetic impurity in multiband superconductors with incipient bands. Contrary to the naive expectation, we found that even if the superconducting (SC) order…
Unlike the widely studied $s$-type two-gap superconductor MgB$_2$, the chemically similar compounds ZrB$_2$ and HfB$_2$ do not superconduct above 1 K. Yet, it has been shown that small amounts of self- or extrinsic doping (in particular…
An inherent difficulty in studying mesoscopic effects in semiconductor--superconductor hybrid structures is the large Schottky barrier which often forms at the interface. A large technological effort has been invested in in improving the…
We analyze the paradigmatic competition between intra-band and cross-band Cooper-pair formation in two-band superconductors, neglected in most works to date. We derive the phase-sensitive gap equations and describe the crossover between the…
``Sub-meV'' resolution photoemission spectroscopy was used to study carbon-substitution dependence on the multiple superconducting gap of Mg(B$_{1 - x}$C$_{x})_{2}$. Two features corresponding to $\sigma $ and $\pi $ gaps are clearly…
In this paper we present a theoretical analysis of the effect of local geometrical structure of the Fermi surface on the surface impedance of a metal at the anomalous skin effect. We show that when the Fermi surface includes nearly…
It is shown that a non-magnetic metallic band in the presence of an antiferromagnetic background coupled only by the exchange interaction develops a superconducting instability similar to the one described by BCS theory plus additional…
We present the results of the first directional point-contact spectroscopy experiments in high-quality MgB_2 single crystals. Due to the directionality of the current injection into the samples, the application of a magnetic field allowed…
We review the current situation in the theory of superconducting and transport properties of MgB2. First principle calculations of of the electronic structure and electron-phonon coupling are discussed and compared with the experiment. We…
Symmetry offers a useful approach to unfold the intertwined degrees of freedom. Thus it paves the way to resolve coexisting quantum orders into distinct symmetry sectors. Motivated by the recent observation of superconductivity in…
We report a detailed study of the electronic structure of the MgB$_{2}$ with different lattice constants by using the full-potential linearized augmented plane wave(FPLAPW) method. It is found that the lattice parameters have great effect…
Superconducting films subject to an in-plane magnetic field exhibit a gapless superconducting phase. We explore the quasi-particle spectral properties of the gapless phase and comment on the transport properties. Of particular interest is…