相关论文: Two-Band-Type Superconducting Instability in MgB2
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 first-principles calculations of the electronic band structure and lattice dynamics for the new superconductor MgB$_{2}$. The excellent agreement between theory and our inelastic neutron scattering measurements of the phonon…
Solid MgB$_2$ has rather interesting and technologically important properties, such as a very high superconducting transition temperature. Focusing on this compound, we report the first non-trivial application of a novel…
We show that in multiband superconductors even small interband proximity effect can lead to a qualitative change in the interaction potential between superconducting vortices by producing long-range intervortex attraction. This type of…
A model for high temperature superconductors based on the idea of Cooper pairs comprised of electrons from different bands is studied. We propose that the two bands relevant for the cuprates are comprised of Cu dx2-y2, dz2, planar O psigma,…
We present a systematic stability analysis for the two-dimensional Hubbard model, which is based on a new renormalization group method for interacting Fermi systems. The flow of effective interactions and susceptibilities confirms the…
The recent observation of superconductivity in proximity to an insulating phase in twisted bilayer graphene (TBG) at small `magic' twist angles has been linked to the existence of nearly-flat bands, which make TBG a fresh playground to…
In the framework of the Ginzburg-Landau approach, we present a self-consistent theory of specific soliton states in mesoscopic (thin-walled) two-band-superconducting cylinders in external parallel magnetic fields. Such states arise in the…
We consider the behaviour of the fluctuating specific heat and conductivity in the vicinity of the upper critical field line for a two-band superconductor. Multiple-band effects are pronounced when the bands have very different coherence…
We study superconductivity in the Hubbard model on various quasi-one-dimensional lattices with coexisting wide and narrow bands originating from multiple sites within a unit cell, where each site corresponds to a single orbital. The systems…
We study the pressure dependence of the superconducting transition temperature of an organic superconductor $\beta'$-(BEDT-TTF)$_2$ICl$_2$ by applying the fluctuation exchange method to the Hubbard model on the original two-band lattice at…
We study a "strongly-coupled" (SC) polariton system formed between the atom-like intersubband transitions in a semiconductor nanostructure and the THz optical modes that are localised at the edges of a gold aperture. The polaritons can be…
We explore multiband effects on d-wave superconducting instabilities driven by electron-electron interactions. Our models on the two-dimensional square lattice consist of a main band with an extended Fermi surface and predominant weight…
Measurements of the superconducting upper critical field, H_{c2}, and critical current density, J_c, have been carried out for MgB_2 doped with Ti and/or C in order to explore the problems encountered if these dopants are used to enhance…
We point out that in two-dimensional systems like high-$T_c$ superconductors, an isotropic s-wave electron-phonon interaction in the momentum decoupling regime leads to either s or d-wave superconductivity depending on the conventional…
The Mott transition in a multi-orbital Hubbard model involving subbands of different widths is studied within the dynamical mean field theory. Using the iterated perturbation theory for the quantum impurity problem it is shown that at low…
We present a careful recasting of first-principles band structure calculations for MgB2 in a non-orthogonal sp-tight-binding (TB) basis. Our TB results almost exactly reproduce our full potential linearized augmented plane wave results for…
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…
We study the non-degenerate one dimensional two-orbital Hubbard model with interorbital Coulomb interaction. By means of the density-matrix renormalization group technique, we calculate the local single-particle density of states and the…
The angular dependence of the upper critical field Hc2 of MgB2 single crystals is studied at various temperatures by means of specific heat and transport measurements in magnetic fields up to 17 T. Clear deviations from Ginzburg-Landau…