Ground-state phase diagram of the generalized Falicov-Kimball model

The extrapolation of small-cluster exact-diagonalization calculations is used to study the ground-state phase diagram of the spin-one-half Falicov-Kimball model (FKM) extended by the spin-dependent on-site interaction between localized (f) and itinerant (d) electrons. Both the magnetic and charge ordering are analysed as functions of the spin-dependent on-site interaction (J) and the total number of itinerant electrons (N-d) at selected values of U (the spin-independent interaction between the localized and itinerant electrons) and N-f (the total number of f-electrons). It is shown that the spin-dependent interaction (for N-f = L) stabilizes the ferromagnetic (FE) and ferrimagnetic (FI) state, while the stability region of anti ferromagnetic (AF) phase is gradually reduced. The precisely opposite effect on the stability of FE, FI and AF phases has a reduction of N-f. Moreover, the strong coupling between the f and d-electron subsystems is found for both N-f = L as well as N-f < L. (c) 2006 Elsevier B.V. All rights reserved.