Superconductivity, Charge Orderings and Phase Separations in Systems with Local Electron Pairing |
| S. Robaszkiewicz and G. Pawłowski Institute of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland |
| Received: June 24, 1996 |
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| We study two effective models developed for description of superconductors with short-coherence length: (i) the extended Hubbard model with on-site attraction and intersite repulsion, (ii) the model of hard-core charged bosons on a lattice. The analysis is concentrated on the problem of phase separations and competition between superconductivity (SS) and charge-density-wave (CDW) orderings. The phase diagrams of the systems are shown to consist of at least seven different states, including 3 types of phase separated (PS) states: CDW-SS (PS1), CDW-normal (PS2) and the state of electron droplets (PS3). By taking into account the PS states and the effects of longer-range density-density interactions (beyond nearest neighbors) our paper substantially generalizes and modifies the conclusions of previous papers concerning the models considered. |
| DOI: 10.12693/APhysPolA.90.569 PACS numbers: 74.20.-z, 05.30.Jp, 71.28.+d |