Monte Carlo Study of Phase Separation in Magnetic Insulators |
| S. Murawski, K.J. Kapcia, G. Pawłowski and S. Robaszkiewicz
Electron States of Solids Division, Faculty of Physics, Adam Mickiewicz University in Poznań, Umultowska 85, 61-614 Poznań, Poland |
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| In this work we focus on the study of phase separation in the zero-bandwidth extended Hubbard with nearest-neighbors intersite Ising-like magnetic interactions J and on-site Coulomb interactions U. The system has been analyzed by means of the Monte Carlo simulations (in the grand canonical ensemble) on two-dimensional square lattice (with N = L × L = 400 sites) and the results for U/(4J) = 2 as a function of chemical potential and electron concentration have been obtained. Depending on the values of interaction parameters the system exhibits homogeneous (anti-)ferromagnetic or non-ordered phase as well as phase separation state. Transitions between homogeneous phases (i.e. antiferromagnetic-non-ordered transitions) can be of first or second order and the tricritical point is also present on the phase diagrams. The electron compressibility K is an indicator of the phase separation and that quantity is of particular interest of this paper. |
DOI: 10.12693/APhysPolA.127.281 PACS numbers: 71.10.Fd, 75.10.-b, 75.30.Fv, 64.75.Gh, 71.10.Hf |