As a model for high- ${\mathit{T}}_{\mathit{c}}$ superconductors, a two-band Hubbard model is proposed. When the Coulomb interactions are introduced between the \ensuremath{\alpha} and \ensuremath{\beta} orbitals, an effective attraction of carriers in the \ensuremath{\beta} (doped) band is shown to arise in an appropriate condition. The quantum Monte Carlo method is used to confirm the occurrence of Cooper pairing in finite two-band Hubbard systems. The attraction, which also appears in the density-density correlation, enhances the on-site singlet Cooper pair-pair correlation in the \ensuremath{\beta} band and suppresses the antiferromagnetic spin-spin correlation in the \ensuremath{\alpha} band. The criterion for the pairing and the nature of the pairing are discussed. Thus we provide a mechanism of superconductivity specific to strongly correlated two-band systems.As a model for high-${\mathit{T}}_{\mathit{c}}$ superconductors, a two-band Hubbard model is proposed. When the Coulomb interactions are introduced between the \ensuremath{\alpha} and \ensuremath{\beta} orbitals, an effective attraction of carriers in the \ensuremath{\beta} (doped) band is shown to arise in an appropriate condition. The quantum Monte Carlo method is used to confirm the occurrence of Cooper pairing in finite two-band Hubbard systems. The attraction, which also appears in the density-density correlation, enhances the on-site singlet Cooper pair-pair correlation in the \ensuremath{\beta} band and suppresses the antiferromagnetic spin-spin correlation in the \ensuremath{\alpha} band. The criterion for the pairing and the nature of the pairing are discussed. Thus we provide a mechanism of superconductivity specific to strongly correlated two-band systems.

Physical review. B, Condensed matterAug 1, 199018 citations

Topological States in Strongly Correlated Systems

V. Yu. Irkhin, Yu. N. Skryabin

arXiv:2209.04336Journal of Superconductivity and Novel MagnetismMay 2, 20225 citations

Orbital Magnetic Correlations, Topological Order, and Superconductivity in Strongly Correlated Systems

V. Yu. Irkhin, Yu. N. Skryabin

Abstract This paper considers modern ideas about the topological nature of superconductivity and the Mott–Hubbard state in strongly correlated systems. These systems are described in terms of spin and charge separation, i.e., deconfinement of spinons and holons in a gauge field. The role of orbital degrees of freedom is discussed. Analogies with topological insulators, quantum Hall effect, and Landau quantization are considered. The importance of the Chern–Simons term for the correct description of the Hubbard splitting is demonstrated.Abstract This paper considers modern ideas about the topological nature of superconductivity and the Mott–Hubbard state in strongly correlated systems. These systems are described in terms of spin and charge separation, i.e., deconfinement of spinons and holons in a gauge field. The role of orbital degrees of freedom is discussed. Analogies with topological insulators, quantum Hall effect, and Landau quantization are considered. The importance of the Chern–Simons term for the correct description of the Hubbard splitting is demonstrated.

The Physics of Metals and MetallographyFeb 1, 20202 citations

As a model for high-

{\mathit{T}}_{\mathit{c}}

superconductors, a two-band Hubbard model is proposed. When the Coulomb interactions are introduced between the \ensuremath{\alpha} and \ensuremath{\beta} orbitals, an effective attraction of carriers in the \ensuremath{\beta} (doped) band is shown to arise in an appropriate condition. The quantum Monte Carlo method is used to confirm the occurrence of Cooper pairing in finite two-band Hubbard systems. The attraction, which also appears in the density-density correlation, enhances the on-site singlet Cooper pair-pair correlation in the \ensuremath{\beta} band and suppresses the antiferromagnetic spin-spin correlation in the \ensuremath{\alpha} band. The criterion for the pairing and the nature of the pairing are discussed. Thus we provide a mechanism of superconductivity specific to strongly correlated two-band systems.