Magnetic Orderings and Phase Separations in the Zero-Bandwidth Limit of the Extended Hubbard Model with Intersite Magnetic Interactions |
| W. Kłobus, K. Kapcia and S. Robaszkiewicz
Electron States of Solids Division, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland |
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| A simple effective model for a description of magnetically ordered insulators is analysed. The tight binding Hamiltonian consists of the effective on-site interaction (U) and intersite magnetic exchange interactions (Jz, Jxy) between nearest neighbours. The phase diagrams of this model have been determined within the variational approach, which treats the on-site interaction term exactly and the intersite interactions within the mean-field approximation. We show that, depending on the values of interaction parameters and the electron concentration, the system can exhibit not only homogeneous phases: (anti-)ferromagnetic (Fα) and nonordered (NO), but also phase separated states (PSα: Fα-NO). |
| DOI: 10.12693/APhysPolA.118.353 PACS numbers: 71.10.Fd, 75.10.-b, 75.30.Gw, 64.75.Gh, 71.10.Hf |