The effects of the next-nearest-neighbour density-density interaction in the atomic limit of the extended Hubbard model

Loading...
Thumbnail Image

Date

2011-03-16

Advisor

Editor

Journal Title

Journal ISSN

Volume Title

Publisher

IOP Publishing Ltd., Temple Circus, Temple Way, Bristol BS1 6BE, England

Title alternative

Abstract

We have studied the extended Hubbard model in the atomic limit. The Hamiltonian analyzed consists of the effective on-site interaction U and the intersite density-density interactions Wij (both: nearest-neighbour and next-nearest-neighbour). The model can be considered as a simple effective model of charge ordered insulators. The phase diagrams and thermodynamic properties of this system have been determined within the variational approach, which treats the on-site interaction term exactly and the intersite interactions within the mean-field approximation. Our investigation of the general case taking into account for the first time the effects of longer-ranged density-density interaction (repulsive and attractive) as well as possible phase separations shows that, depending on the values of the interaction parameters and the electron concentration, the system can exhibit not only several homogeneous charge ordered (CO) phases, but also various phase separated states (CO-CO and CO-nonordered). One finds that the model considered exhibits very interesting multicritical behaviours and features, including among others bicritical, tricritical, critical-end and isolated critical points.

Description

This is an author-created, un-copyedited version of an article accepted for publication in Journal of Physics: Condensed Matter. IOP Publishing Ltd. is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at http://dx.doi.org/10.1088/0953-8984/23/10/105601

Sponsor

Keywords

charge orderings, phase separations, extended Hubbard model, atomic limit

Citation

Journal of Physics: Condensed Matter, Vol. 23, No. 10, 105601 (1-12) (2011)

ISBN

Title Alternative

Rights Creative Commons

Creative Commons License

Uniwersytet im. Adama Mickiewicza w Poznaniu
Biblioteka Uniwersytetu im. Adama Mickiewicza w Poznaniu
Ministerstwo Nauki i Szkolnictwa Wyższego