Stable and Metastable Phases in the Atomic Limit of the Extended Hubbard Model with Intersite Density-Density Interactions

• Authors: K. Kapcia , S. Robaszkiewicz
• Languages of publication: EN

Abstracts

EN

We have studied a simple effective model of charge ordered insulators. The tight binding Hamiltonian consists of the effective on-site interaction U and the intersite density-density interaction W_{ij} (both: nearest-neighbor and next-nearest-neighbor). In the analysis of the phase diagrams and thermodynamic properties of this model we have adopted the variational approach, which treats the on-site interaction term exactly and the intersite interactions within the mean-field approximation. Our investigations of the general case (as a function of the electron concentration n) have shown that the system exhibits various critical behaviors including among others bicritical, tricritical, critical-end, and isolated critical points. In this report we concentrate on the metastable phases and transitions between them. One finds that the first- and second order transitions between metastable phases can exist in the system. These transitions occur in the neighborhood of first as well as second order transitions between stable phases. For the case of on-site attraction the regions of metastable homogeneous phases occurrence inside the ranges of phase separated states stability have been also determined.

Keywords

EN

71.10.Fd; 71.45.Lr; 64.60.My; 64.75.Gh; 71.10.Hf

Discipline

• 64.60.My: Metastable phases
• 71.45.Lr: Charge-density-wave systems(see also 75.30.Fv Spin-density waves)
• 71.10.Fd: Lattice fermion models (Hubbard model, etc.)
• 71.10.Hf: Non-Fermi-liquid ground states, electron phase diagrams and phase transitions in model systems
• 64.75.Gh: Phase separation and segregation in model systems (hard spheres, Lennard-Jones, etc.)

• Publisher: Institute of Physics, Polish Academy of Sciences
• Journal: Acta Physica Polonica A
• Year: 2012
• Volume: 121
• Issue: 5-6
• Pages: 1029-1031

Dates

published

2012-05

Contributors

author

K. Kapcia

• Electron States of Solids Division, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland

author

S. Robaszkiewicz

• Electron States of Solids Division, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland

References

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Identifiers

DOI

10.12693/APhysPolA.121.1029