Related papers: Relativistic Model for two-band Superconductivity
We investigate a collective excitation (Leggett's mode) corresponding to small fluctuations of the relative phase of two condensates in two-band superconductor using the effective ``phase only'' action. We consider the possibility of…
To identify the contributions of the multiband nature and the anisotropy of a microscopic electronic structure to a macroscopic vortex lattice morphology, we develop a method based on the Eilenberger theory near Hc2 combined with the…
The high transition temperature and low surface resistance of MgB2 attracts interest in its potential application in superconducting radio frequency accelerating cavities. However, compared to traditional Nb cavities, the viability of MgB2…
Realistic selfconsistent calculations of unconventional superconductivity in a heavy-fermion material are reported. Our calculations for UPd$_2$Al$_3$ start from accurate energy band dispersions that are computed within the local…
Using the tight-binding method for the $\pi$-bands in MgB$_2$, the Hubbard on-site Coulomb interaction on two inequivalent boron $p_z$-orbitals is transformed into expressions in terms of $\pi$-band operators. For scattering processes…
We developed a parabolic effective mass model with the aim to describe the in-plane constricted superconductivity in few-monolayer MgB$_2$. The model was employed to study a constricted quasi-$1$D superlattice with the simplest version of…
We analyse the pairing symmetry of the order parameter in superconducting Sr2RuO4. Basing on a realistic three dimensional 3 band energy spectrum we have introduced effective attractive ellectron-electron interactions and found a solution…
Recently we have proposed a s+g-wave model for the superconductivity in borocarbides, YNi2B2C and LuNi2B2C. In the present paper we first summarize thermodynamic properties of s+g-wave model. Then we shall analyse the recent Raman spectra…
We have theoretically investigated two-band models of graded-gap superlattices within the envelope-function approximation. Assuming that the gap varies linearly with spatial coordinate, we are able to find exact solutions of the…
According to the crystal structure of MgB$_{2}$ and band structure calculations quasi-two-dimensional (2D) boron planes are responsible for the superconductivity. We report on critical fields and resistance measurements of 30 nm thick…
We explore how the superconductivity arising from the on-site electron-electron repulsion will change when the repulsion is changed to a long-ranged, 1/r-like one by introducing an extended Hubbard model with the repulsion extending to…
First principles FLMTO-GGA electronic structure calculations of the new medium-$T_C$ superconductor (MTSC) $MgB_2$ and related diborides indicate that superconductivity in these compounds is related to the the existence of $p_{x,y}$-band…
Superconducting properties of hypothetical simple hexagonal CaB2 are studied using the fully anisotropic Eliashberg formalism based on electronic and phononic structures and electron-phonon interactions which are obtained from ab initio…
We address the question of how phonons of various frequencies contribute to the superconducting transition temperature $T_c$ of a multi-band superconductor by considering the functional derivatives of $T_c$ with respect to various intraband…
In this paper we developed theory of the ferrimagnetism in the Hubbard model on bipartite lattices with spectrum symmetry. We then study the defect-induced ferrimagnetic orders in three models and explored the universal features.
We formulate a generalized pseudospin formalism for multiband superconductors in the presence of an external perturbing electromagnetic field. Our theory naturally captures the effects of quantum band geometric quantities and is valid even…
The relativistic generalization of the theory of superconductivity is reviewed with respect to its conceptual basis and first applications. The construction of relativistically covariant order parameters for superconductors is outlined and…
Recent theoretical studies of various strongly-correlated systems in condensed matter physics reveal that the lattice gauge theory(LGT) developed in high-energy physics is quite a useful tool to understand physics of these systems.…
One promising way to enhance superconductivity is to have coexisting wide and incipient narrow bands, where the Fermi level intersecting the wide band lies just above the narrow band, by which finite-energy spin fluctuations act as glue to…
We present theoretical calculations of collective modes of the one-band attractive Hubbard model which is widely used to study the s-wave superfluid phases of atomic Fermi gases of two-hyperfine states loaded in a deep optical lattice. To…