Charge Ordering and Phase Separations in the Spinless Fermion Model with Repulsive Intersite Interaction

W.R. Czart, S. Robaszkiewicz and B. Tobijaszewska Institute of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland

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Received: 6 11 2007;

We study a simple effective model for description of charge orderings in narrow band materials, i.e. the spinless fermion model with repulsive intersite interaction W. The analysis is concentrated on the problem of phase separations and the effects of next-nearest neighbor hopping t2 on the charge ordered states in this system. The cases of d-dimensional (d ≥ 2) hypercubic lattices are considered for arbitrary particle concentration (0 < n < 1). Within the broken symmetry Hartree-Fock approximation the phase diagrams as a function of W and n are evaluated for representative cases. The results for t2 ≠ 0 are compared with those found for the case with nearest neighbor hopping only.

DOI: 10.12693/APhysPolA.114.129 PACS numbers: 71.10.Fd, 71.30.+h, 71.45.Lr, 64.75.Gh