Related papers: Self-consistent Eliashberg theory, Tc, and the gap…
Developing a theory of high-temperature superconductivity in copper oxides is one of the outstanding problems in physics. It is a challenge that has defeated theoretical physicists for more than twenty years. Attempts to understand this…
Near a two-dimensional Ising-type nematic quantum critical point, the quantum fluctuations of the nematic order parameter are coupled to the electrons, leading to non-Fermi liquid behavior and unconventional superconductivity. The interplay…
The pseudogap phenomena in High-$T_{{\rm c}}$ cuprates are investigated on the basis of the Hubbard model which includes only the on-site repulsive interaction $U$. We consider the pairing scenario for the pseudogap. The pseudogap arises…
We study the pairing of fermions by an interaction consisting of a Hubbard repulsion, mimicking a screened Coulomb potential, and a dynamical phonon-mediated attraction. For such interaction, the gap equation allows even- and odd-frequency…
Using a large-N expansion we present and solve the linearized equation for the superconducting gap for a generalized t-J model which also contains phonons within a Holstein model. The leading Tc has d-wave symmetry with phonons giving a…
The complete scenario of high-Tc superconductivity based on experimental data from electron-tunneling spectroscopy on underdoped, overdoped and Ni-doped Bi2212 single crystals using a break-junction technique is presented. There are two…
Applying a variational Monte Carlo method to a two-dimensional t-J model, we study the nonmonotonic d_{x^2-y^2}-wave superconductivity, observed by Raman scattering and ARPES experiments in the electron-doped cuprates. As a gap function in…
Deviations from Fermi liquid behavior are well documented in the normal state of the cuprate superconductors, and some of these differences seem to be related to pre-transitional features appearing at temperatures above T$_c$. The…
A microscopic theory of spin excitations in strongly-correlated electronic systems within the t-J model is discussed. An exact representation for the dynamic spin susceptibility is derived. In the normal state, the excitation spectrum…
The question of pairing glue for the cuprate superconductors (SC)is revisited and its determination through the angle resolved photo-emission spectroscopy (ARPES) is discussed in detail. There are two schools of thoughts about the pairing…
The doping dependence of the superconducting state for the 2D one-band Hubbard Hamiltonian is determined. By using an Eliashberg-type theory, we find that the gap function $\Delta_{\bf k}$ has a $d_{x^2-y^2}$ symmetry in momentum space and…
Recently it was revealed that the whole Fermi surface is fully gapped for several families of underdoped cuprates. The existence of the finite energy gap along the $d$-wave nodal lines ("nodal gap") contrasts the common understanding of the…
The question of whether the pseudogap in high $T_c$ cuprates is related to super conducting precursor effects or to the existence of extrinsic bosonic massive excitations is investigated on the basis of the Boson-Fermion model. The…
A strategy to enhance d-wave superconducting correlations is proposed based on our numerical study for correlated electron models for high-Tc cuprates. We observe that the pairing is enhanced when the single-electron level around (pi,0) is…
The pseudogap phenomena in the cuprate superconductors requires a theory beyond the mean field BCS level. A natural candidate is to include strong pairing fluctuations, and treat the two-particle and single particle Green's functions…
A scenario is presented, in which the presence of a quantum critical point due to formation of incommensurate charge density waves accounts for the basic features of the high temperature superconducting cuprates, both in the normal and in…
We study electronic structure of hole- and electron-doped Mott insulators in the two-dimensional Hubbard model to reach a unified picture for the normal state of cuprate high-Tc superconductors. By using a cluster extension of the dynamical…
We consider the Cooper-problem on a lattice model including onsite and near-neighbor interactions. Expanding the interaction in basis functions for the irreducible representation for the point group $C_{4v}$ yields a classification of the…
In weakly coupled BCS superconductors, only electrons within a tiny energy window around the Fermi energy, $E_F$, form Cooper pairs. This may not be the case in strong coupling superconductors such as cuprates, FeSe, SrTiO$_3$ or cold atom…
We present the theory of the leading edge gap in the normal state of underdoped high-$T_c$ materials. The consideration is based on a magnetic scenario for cuprates. We show that as doping decreases, the increasing interaction with…