A simple model description is proposed for the superconducting state of a highly correlated, homogeneous electron liquid. The mathematical apparatus is based on the method of the (u,v)-transformation and the basic inclusion of correlation effects. It is demonstrated that the existence of the superconducting phase is attributable to lag effects, which induce an effective attraction between electrons having momenta close to the Fermi momentum. The characteristics of the superconducting phase are investigated as functions of the nonideality parameter.A simple model description is proposed for the superconducting state of a highly correlated, homogeneous electron liquid. The mathematical apparatus is based on the method of the (u,v)-transformation and the basic inclusion of correlation effects. It is demonstrated that the existence of the superconducting phase is attributable to lag effects, which induce an effective attraction between electrons having momenta close to the Fermi momentum. The characteristics of the superconducting phase are investigated as functions of the nonideality parameter.

Low Temperature PhysicsJul 1, 19950 citations

Effect of superconducting correlation on the localization of quasiparticles in low dimensions

Tao Xiang

Localization lengths of superconducting quasiparticles ${\ensuremath{\lambda}}_{\mathit{s}}$ are evaluated and compared with the corresponding normal-state values ${\ensuremath{\lambda}}_{\mathit{n}}$ in one-dimensional (1D) and two-dimensional lattices. The effect of superconducting correlation on the localization of quasiparticles is generally stronger in an off-site pairing state than in an on-site pairing state. The modification of superconducting correlation to \ensuremath{\lambda} is strongly correlated with the density of states (DOS) of superconducting quasiparticles. ${\ensuremath{\lambda}}_{\mathit{s}}$ drops within the energy gap but is largely enhanced around energies where DOS peaks appear. For a gapless pairing state in 1D or a d-wave pairing state in 2D, ${\ensuremath{\lambda}}_{\mathit{s}}$/${\ensuremath{\lambda}}_{\mathit{n}}$ at the Fermi energy ${\mathit{E}}_{\mathit{F}}$ is of order 1 and determined purely by the value of gap parameter not by the random potential. For the d-wave pairing state, the localization effect is largely weakened compared with the corresponding normal state and quasiparticles with energies close to ${\mathit{E}}_{\mathit{F}}$ are more strongly localized than other low-energy quasiparticles.Localization lengths of superconducting quasiparticles ${\ensuremath{\lambda}}_{\mathit{s}}$ are evaluated and compared with the corresponding normal-state values ${\ensuremath{\lambda}}_{\mathit{n}}$ in one-dimensional (1D) and two-dimensional lattices. The effect of superconducting correlation on the localization of quasiparticles is generally stronger in an off-site pairing state than in an on-site pairing state. The modification of superconducting correlation to \ensuremath{\lambda} is strongly correlated with the density of states (DOS) of superconducting quasiparticles. ${\ensuremath{\lambda}}_{\mathit{s}}$ drops within the energy gap but is largely enhanced around energies where DOS peaks appear. For a gapless pairing state in 1D or a d-wave pairing state in 2D, ${\ensuremath{\lambda}}_{\mathit{s}}$/${\ensuremath{\lambda}}_{\mathit{n}}$ at the Fermi energy ${\mathit{E}}_{\mathit{F}}$ is of order 1 and determined purely by the value of gap parameter not by the random potential. For the d-wave pairing state, the localization effect is largely weakened compared with the corresponding normal state and quasiparticles with energies close to ${\mathit{E}}_{\mathit{F}}$ are more strongly localized than other low-energy quasiparticles.

arXiv:cond-mat/9503152Physical review. B, Condensed matterSep 1, 19955 citations

Superconductivity due to coulomb interactions

S. Küchenhoff, Stephan Schiller

Physica B Condensed MatterAug 1, 19903 citations

Superconducting phases in the presence of Coulomb interaction: From weak to strong correlations

T. Domański, Karol Izydor Wysokiński

We study the evolution of the superconducting phases in a model with competing short-range attractive (W) and on-site repulsive (U) interactions. The influence of the correlations on the phase diagram of $s\ensuremath{-}$ and d-wave superconductors is studied by means of various approximations. The knowledge of the normal state correlation effects allows the tracking of the influence of U on the superconductivity in correlated systems. We have found the qualitatively different response of the superconducting phases in systems with $W<{U}_{\mathrm{cr}},$ when the system ceases to superconduct for large enough U, and in the limit of strong $W>{U}_{\mathrm{cr}},$ when the system remains superconducting for arbitrarily large U.We study the evolution of the superconducting phases in a model with competing short-range attractive (W) and on-site repulsive (U) interactions. The influence of the correlations on the phase diagram of $s\ensuremath{-}$ and d-wave superconductors is studied by means of various approximations. The knowledge of the normal state correlation effects allows the tracking of the influence of U on the superconductivity in correlated systems. We have found the qualitatively different response of the superconducting phases in systems with $W<{U}_{\mathrm{cr}},$ when the system ceases to superconduct for large enough U, and in the limit of strong $W>{U}_{\mathrm{cr}},$ when the system remains superconducting for arbitrarily large U.

Physical review. B, Condensed matterJan 1, 199915 citations

Superconductivity from Strong Correlation in High-Temperature Superconductors

Takashi Yanagisawa, Mitake Miyazaki, Yamaji K.

Journal of Superconductivity and Novel MagnetismDec 9, 20152 citations

{\mathit{E}}_{\mathit{F}}

is of order 1 and determined purely by the value of gap parameter not by the random potential. For the d-wave pairing state, the localization effect is largely weakened compared with the corresponding normal state and quasiparticles with energies close to

{\mathit{E}}_{\mathit{F}}

are more strongly localized than other low-energy quasiparticles.

W<{U}_{\mathrm{cr}},

when the system ceases to superconduct for large enough U, and in the limit of strong

W>{U}_{\mathrm{cr}},

when the system remains superconducting for arbitrarily large U.