Influence of f-Electron Hopping On Valence Transition of Mixed-Valent Systems

Abstract

The contribution of f-electron hopping has been studied on a four-sitesquare cluster in an exact diagonalization method using extended Falicov-Kimball model. It appears that f-f hopping shifts the critical f-level energy(Ec) at which valence transition occurs. So far entropy is concerned, f-fhopping increases disorder in the system. Both, single and double-peakstructures are obtained in specific heat curves. The peak height decreaseswith higher negativity of f-electron hopping. That indicates a reduction inthe number of the density of states. Spin susceptibility (χ) characteristicsshow Curie-like nature as well as antiferromagnetic ordering which growswith f-f hopping.