Electronic excitation spectra of the Emery model

Unger, P.P.; Fulde, Peter

doi:10.1103/physrevb.47.8947

Cited by 30 publications

(12 citation statements)

References 27 publications

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“…This model was initially derived by a canonical transformation from the Hubbard model near the half-filling, n → 1, in the limit t/U << 1 [131,132]. Later on, for cuprates, a generalized t − J model was suggested [133,134], The Hamiltonian of the generalized 2D t − J model with a weakened constraint and an arbitrary ratio J/t derived from the three-band Emery model [135,136] is written as [133,134,137] [96,137].…”

Section: Superconductivity In the 2d T-j Modelmentioning

confidence: 99%

Anomalous superconductivity and superfluidity in repulsive fermion systems

2015

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We discuss the mechanisms of unconventional superconductivity and superfluidity in 3D and 2D fermionic systems with purely repulsive interaction at low densities. We construct phase diagrams of these systems and find the areas of the superconducting state in free space, as well as on the lattice in the framework of the Fermi-gas model with hard-core repulsion, the Hubbard model, the Shubin-Vonsovsky model, and the t − J model. We demonstrate that the critical superconducting temperature can be greatly increased in the spin-polarized case or in a two-band situation already at low densities. The proposed theory is based on the Kohn-Luttinger mechanism or its generalizations and explains or predicts anomalous p-, d-, and f -wave pairing in various materials, such as high-temperature superconductors, the idealized monolayer and bilayer of doped graphene, heavy-fermion systems, layered organic superconductors, superfluid 3 He, spin-polarized 3 He mixtures in 4 He, ultracold quantum gases in magnetic traps, and optical lattices.

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Section: Superconductivity In the 2d T-j Modelmentioning

confidence: 99%

Anomalous superconductivity and superfluidity in repulsive fermion systems

2015

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“…34 Using the projection technique developed by Becker and Fulde 35 these authors constructed an equation of motion for single-particle spectral functions of the CuO 2 plane, which is very similar to the ones which would be obtained from our effective Hamiltonians. Finally we address the work of Bala et al, 21 which is very similar in spirit to the present theory.…”

Section: Discussionmentioning

confidence: 91%

Single-particle spectra of charge-transfer insulators by cluster perturbation theory: The correlated band structure of NiO

2005

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We propose a many-body method for band-structure calculations in strongly correlated electron systems and apply it to NiO. The method may be viewed as a translationally invariant version of the cluster method of Fujimori and Minami. Thereby the Coulomb interaction within the d-shells is treated by exact diagonalization and the d-shells then are coupled to a solid by an extension of the cluster perturbation theory due to Senechal et al. The method is computationally no more demanding than a conventional band structure calculation and for NiO we find good agreement between the calculated single particle spectral function and the experimentally measured band structure.

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“…As it stands, however, it is too oversimplified to explain the physics of doped Mott-Hubbard insulators at large. For instance, in its application to the HTS, the hole spectral functions obtained from this model [13,22] do reproduce only the low-energy part of the spectra obtained either by the exact diagonalization of Cu4O12 cluster [62], or from the strong-coupling analytic treatment of the Emery model [63]. Thus, they have been successfully applied to the optical properties of HTS [64], but cannot explain the photoemission spectra.…”

Section: Discussionmentioning

confidence: 99%

Magnetic Phases and Generalized t-J Models in Doped Mott-Hubbard Insulators

Oleś

Zaanen

1994

Acta Phys. Pol. A

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We review some recent results obtained for the dynamics of a single hole and for the ground states at finite hole doping in t-J model. Next, we address the role of orbital degeneracy in doped Mott-Hubbard insulators and show examples of effective strong coupling models which include the orbital degrees of freedom. These new-t-J models have interesting phase diagrams, with the new magnetic phases stabilized by a competition between magnetic energy and excitonic excitations. It is argued that the doped holes always bind to the excitons and that the new phases identified on the mean-field level give rise to local distortions of the lattice. We conclude that realistic t-J models derived from the electronic structure of particular compounds may be successfully applied for understanding both the observed magnetic ground states, and the results of photoemission experiments, as we have demonstrated recently for NiO. Hole doping in t-J modelStrongly correlated fermions occur in nature in heavy-fermion systems, high temperature superconductors (HTS), doped Mott-Hubbard insulators, in 3 He, and in neutron stars. Generally speaking, these systems involve orbitally degenerate states, as 3d or 4f (5f) states. Yet, in the most common approach to describe the strongly correlated electrons the orbital degrees of freedom are ignored and the problem is reduced to that of spin degeneracy alone. While the nondegenerate Hubbard model, describing the electron correlations in the nondegenerate s band has been used with some success to describe the physical properties of 3 He [1], the attempts to classify various magnetic, charge order, and superconducting instabilities observed in solid state physics in terms of electrons interacting within (145)

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Electronic excitation spectra of the Emery model

Cited by 30 publications

References 27 publications

Anomalous superconductivity and superfluidity in repulsive fermion systems

Anomalous superconductivity and superfluidity in repulsive fermion systems

Single-particle spectra of charge-transfer insulators by cluster perturbation theory: The correlated band structure of NiO

Magnetic Phases and Generalized t-J Models in Doped Mott-Hubbard Insulators

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