Interplay and competition between superconductivity and charge orderings in the zero-bandwidth limit of the extended Hubbard model with pair hopping and on-site attraction
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Date
2013-08
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Springer
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Abstract
We present studies of an effective model which is a simple generalization of the standard model of a local pair superconductor with on-site pairing (i.e., the model of hard core bosons on a lattice) to the case of finite pair binding energy. The tight binding Hamiltonian consists of (i) the effective on-site interaction U, (ii) the intersite density-density interactions W between nearest-neighbours, and (iii) 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. Our investigations of the U<0 and W>0 case show that, depending on the values of interaction parameters, the system can exhibit three homogeneous phases: superconducting (SS), charge-ordered (CO) and nonordered (NO) as well as the phase separated SS-CO state.
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This is an author-created, un-copyedited version of an article accepted for publication in Journal of Superconductivity and Novel Magnetism.
Sponsor
National Science Center (NCN) as a research project in years 2011-2013, under grant No. DEC-2011/01/N/ST3/00413;
European Commission and Ministry of Science and Higher Education (Poland) - partial financial support from European Social Fund – Operational
Programme "Human Capital" – POKL.04.01.01-00-133/09-00 – "Proinnowacyjne kształcenie, kompetentna kadra, absolwenci przyszłości";
The Fundation of Adam Mickiewicz University in Poznań
Keywords
superconductivity, charge orderings, extended Hubbard model, atomic limit, phase separation, local pairing
Citation
Journal of Superconductivity and Novel Magnetism, Vol. 26, No. 8, 2647-2650 (2013)