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On the Phase Diagram of the Zero-Bandwidth Extended Hubbard Model with Intersite Magnetic Interactions for Strong On-Site Repulsion Limit

2012; Polish Academy of Sciences; Volume: 121; Issue: 5-6 Linguagem: Inglês

10.12693/aphyspola.121.1035

1898-794X

Szymon Murawski, Konrad Jerzy Kapcia, Grzegorz Pawłowski, S. Robaszkiewicz,

Physics of Superconductivity and Magnetism

In this report we have analyzed a simple effective model for a description of magnetically ordered insulators.The Hamiltonian considered consists of the effective on-site interaction (U ) and the intersite Ising-like magnetic exchange interaction (J) between nearest neighbors.For the first time the phase diagrams of this model have been determined within Monte Carlo simulation on 2D-square lattice.They have been compared with results obtained within variational approach, which treats the on-site term exactly and the intersite interactions within mean-field approximation.We show within both approaches that, depending on the values of interaction parameters and the electron concentration, the system can exhibit not only homogeneous phases: (anti-)ferromagnetic (F) and nonordered (NO), but also phase separated states (PS: F-NO).