Related papers: Energy Gaps and Kohn Anomalies in Elemental Superc…
We studied the influence of the amplitude fluctuations of a non-Fermi superconductor on the energy spectrum of the 2D Anderson non-Fermi system. The classical fluctuations give a temperature dependence in the pseudogap induced in the…
We investigate the electronic structure of the 2H and 3R polytypes of NbS$_2$. The Fermi surfaces measured by angle-resolved photoemission spectroscopy show a remarkable difference in size, reflecting a significantly increased band filling…
Ultrafast optical spectroscopy is used to study the antiferromagnetic f-electron system USb2. We observe the opening of two charge gaps at low temperatures (<45 K), arising from renormalization of the electronic structure. Analysis of our…
We elucidate the origin of the phonon-mediated superconductivity in 2$H$-NbS$_2$ using the ab initio anisotropic Migdal-Eliashberg theory including Coulomb interactions. We demonstrate that superconductivity is associated with Fermi surface…
Recent experiments suggest that besides of antiferromagnetic fluctuations nematic fluctuations may contribute to the occurrence of superconductivity in iron pnictides. Motivated by this observation we study superconductivity from nematic…
We uncover that the competition between electron-electron correlations and electron-phonon interactions gives rise to unexpectedly huge enhancement of the superconducting transition temperature, several hundreds percent larger ($\geq$ 200…
In this work, a question is tackled concerning the formation of a superconducting condensate in an earlier proposed model of "elastic jelly", in which phonons of the valent skeleton play the part of initiating ones. It was shown that in…
The lack of nesting of the electron and hole Fermi-surface sheets in the Fe-based superconductor LiFeAs, with a critical temperature of 18 K, has led to questions as to whether the origin of superconductivity in this material might be…
The resonance, a collective boson mode, was usually thought to be a possible glue of superconductivity. We argue that it is rather a natural product of the \emph{d}-wave pairing and the Fermi surface topology. A universal scaling…
We analyze the magnetic excitations and the spin-mediated superconductivity in iron-based superconductors within a low-energy model that operates in the band basis but fully incorporates the orbital character of the spin excitations. We…
The normal state behaviour of the density of states of the electrons described by the BOSON - FERMION model for Bose-Einstein condensation driven superconductivity is characterized by the appearence of a pseudogap which developes into a…
We analyze the influence of a local pairing on the quantum interference in nanoscopic systems. As a model system we choose the double quantum dot coupled to one metallic and one superconducting electrode in the T-shape geometry. The…
The superconducting order parameter and electron-phonon interaction (EPI) in a MgB$_{2}$ c-axis oriented thin film are investigated by point contacts (PCs). Two superconducting gaps $\Delta_{Small}\approx 2.6$ meV and $\Delta_{Large}\approx…
We investigate low-temperature electronic properties of the nondimeric organic superconductor $\beta^{\prime\prime}$-(BEDT-TTF)$_4$[(H$_3$O)Ga(C$_2$O$_4$)$_3$]PhNO$_2$. By examining ultrasonic properties, charge disproportionation (CD)…
This paper studies the physics of junctions containing superconducting $(S)$ and normal $(N)$ leads weakly coupled to an Anderson impurity in the Kondo regime $(K)$. Special attention is devoted to the case where one of the leads is a…
Many superconducting devices rely on the finite gap in the excitation spectrum of a superconductor: thanks to this gap, at temperatures much smaller than the critical one the number of excitations (quasiparticles) that can impact the…
We calculate superconducting gaps and quasiparticle density of states of YNi$_2$B$_2$C in the framework of the density functional theory for superconductors to investigate the origin of a highly anisotropic superconducting gaps in this…
Partial nesting between two connected or disconnected regions of the Fermi surface leads to fractional powers of the Coulomb scattering lifetime as a function of temperature and frequency. This result is first demonstrated for a toy band…
The electron-phonon and spin-phonon coupling in typical high-T_C cuprates, like LSCO and HBCO are peaked for just a few q-vectors because of the 2-dimensional Fermi surface shape. The activation of few spin-phonon modes compensates for the…
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…