Electron phase separations involving superconductivity in the extended Hubbard models with pair hopping interaction

This is an author-created, un-copyedited version of an article accepted for publication in Acta Physica Polonica A.In this work the extended Hubbard models with pair hopping interaction (at the atomic limit) are investigated within the variational approach, which treats the on-site interaction term exactly and the intersite interactions within the mean-field approximation (exact in $d\rightarrow+\infty$). We analyze mutual stability of the superconducting (SC) phase and charge (CO) or (ferro/antiferro-)magnetic (M) orderings as well as homogeneous mixed phases. Our preliminary results for U=0 show that the SC phase can coexist with the CO or M phases only in states with electron phase separation.National Science Center (NCN) as a research project in years 2011-2013, under grant No. DEC-2011/01/N/ST3/00413; National Science Center (NCN) as a doctoral scholarship in years 2013-2014 No. DEC- 2013/08/T/ST3/00012; 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