The role of intra- and inter-site exchange correlations in the extended Falicov–Kimball model on a triangular lattice

Abstract

Ground state magnetic properties of the spin-dependent Falicov-Kimball model (FKM) are studied by incorporating the intrasite exchange correlation J (between itinerant $d$- and localized $f$- electrons) and intersite (superexchange) correlation $J_{se}$ (between localized $f$- electrons) on a triangular lattice for two different fillings. Numerical diagonalization and Monte-Carlo techniques are used to determine the ground state magnetic properties. Transitions from antiferromagnetic to ferromagnetic and again to re-entrant antiferromagnetic phase is observed in a wide range of parameter space. The magnetic moments of $d$- and $f$- electrons are observed to depend strongly on the value of $J$, $J_{se}$ and also on the total number of $d$- electrons ($N_d$).