Related papers: Field-induced superconductivity mediated by odd-pa…
Systems with strong electronic Coulomb correlations often display rich phase diagrams exhibiting different ordered phases involving spin, charge, or orbital degrees of freedom. The theoretical description of the interplay of the…
The pairing symmetry in the electron mechanism for superconductivity is explored when charge fluctuations coexist with spin fluctuations. The extended Hubbard model is adopted to obtain, with the fluctuation exchange approximation, a phase…
When interacting electrons are confined to low-dimensions, the electron-electron correlation effect is enhanced dramatically, which often drives the system into exhibiting behaviors that are otherwise highly improbable. Superconductivity…
Understanding the interplay between magnetism and superconductivity is one of the central issues in condensed matter physics. Such interplay induced nodal structure of superconducting gap is widely believed to be a signature of exotic…
In all known superconductors the pairing of fermions is not sensitive to the sign of their time-argument difference, leading to a Cooper pair wavefunction that is even in time/frequency. Four decades ago it was suggested that odd-frequency…
We consider a two-orbital impurity system with intra and inter-level Coulomb repulsion that is coupled to a single conduction channel. This situation can generically occur in multilevel quantum dots or in systems of coupled quantum dots.…
The synthetic organic compound lambda-(BETS)2FeCl4 undergoes successive transitions from an antiferromagnetic insulator to a metal and then to a superconductor as a magnetic field is increased. We use a Hubbard-Kondo model to clarify the…
When a biased conductor is put in proximity with an unbiased conductor a drag current can be induced in the absence of detailed balance. This is known as the Coulomb drag effect. However, even in this situation far away from equilibrium…
Superconductivity and polar charge fluctuation are studied in an organic conductor with the dimer-molecule degree of freedom. The extended Hubbard models, where the intra-dimer electronic structure and the inter-dimer Coulomb interactions…
Nonequilibrium conditions offer novel routes to superconductivity that are not available at equilibrium. For example, by engineering nonequilibrium electronic populations, pairing may develop between electrons in different energy bands. A…
The semiclassical Coulomb excitation interaction is at times expressed in the Lorentz gauge in terms of the electromagnetic fields and a contribution from the scalar electric potential. We point out that the potential term can make spurious…
We consider a system where localized bound electron pairs form an array of "Andreev"-like scattering centers and are coupled to a fermionic subsystem of uncorrelated electrons. By means of a path-integral approach, which describes the bound…
High-$T_c$ superconductivity is unconventional because the gap is not isotropic as in simple metals but has $d_{x^2-y^2}$ symmetry with lines of nodes. In a fascinating thermal transport experiment on a high-$T_c$ superconductor, Krishana…
In order to discuss superconductivity in orbital degenerate systems, a microscopic Hamiltonian is introduced. Based on the degenerate model, a strong-coupling theory of superconductivity is developed within the fluctuation exchange (FLEX)…
In iron pnictides, we find that the moderate electron-phonon interaction due to the Fe-ion oscillation can induce the critical d-orbital fluctuations, without being prohibited by the Coulomb interaction. These fluctuations give rise to the…
Superconductivity had been one of the most enigmatic phenomena in condensed matter physics, puzzling the best theorists for 45 years, since the original discovery by Kamerlingh-Onnes in 1911 till the final solution by Bardeen, Cooper and…
Superconductors exhibit a nonlinear interaction with an applied light, which can resonantly excite the collective amplitude (Higgs) mode. Here we study light-induced dynamics of layered superconductors, where each layer is coupled to…
We present a theory of superconductivity in twisted bilayer graphene in which attraction is generated between electrons on the same honeycomb sublattice when the system is close to a sublattice polarization instability. The resulting Cooper…
Full or empty narrow bands near the Fermi level are known to enhance superconductivity by promoting scattering processes and spin fluctuations. Here, we demonstrate that doublon-holon fluctuations in systems with half-filled narrow bands…
We study the effect of a strong electric field on the fluctuation conductivity within the time-dependent Ginzburg-Landau theory for the case of arbitrary dimension. Our results are based on the analytical derivation of the velocity…