Metastability and phase separation in a simple model of a superconductor with extremely short coherence length

Abstract

We present studies of the atomic limit of the extended Hubbard model with pair hopping for arbitrary electron density and arbitrary chemical potential. The Hamiltonian consists of (i) the effective on-site interaction $U$ and (ii) the intersite charge exchange term $I$, determining the hopping of electron pairs between nearest-neighbour sites. In the analysis of the phase diagrams and thermodynamic properties of this model we treat the intersite interactions within the mean-field approximation. In this report we focus on metastable phases and determine their ranges of occurrence. Our investigations in the absence of the external magnetic field show that the system analysed exhibits tricritical behaviour. Two metastable phases (superconducting and nonordered) can exist inside the regions of the phase separated state stability and a first-order transition occurs between these metastable phases.

5 pages, 3 figures; pdf-ReVTeX; submitted to: Journal of Superconductivity and Novel Magnetism

References in corpus (5)

• One-dimensional extended Hubbard model in the atomic limit
• Fulde-Ferrell-Larkin-Ovchinnikov phase in the presence of pair hopping interaction
• Phase separation in a lattice model of a superconductor with pair hopping
• Critical field in a model with local pairs
• The magnetic field induced phase separation in a model of a superconductor with local electron pairing

Cited by in corpus (7)

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• Extended Falicov-Kimball model: Exact solution for finite temperatures
• Charge-Order on the Triangular Lattice: A Mean-Field Study for the Lattice $S=1/2$ Fermionic Gas
• Critical Temperatures of Hard-Core Boson Model on Square Lattice within Bethe Approximation
• Magnetic and charge orders on the triangular lattice: Extended Hubbard model with intersite Ising-like magnetic interactions in the atomic limit