Finite-temperature behavior of the Anderson lattice

Abstract

At finite temperature the picture of renormalized-hybridization quasiparticle bands, obtained by various formalisms at T=0, is shown to be inadequate in several respects. The most significant refinement recognizes the existence of a new type of elementary excitation, which simply creates (i.e., unbinds or unscreens) a local moment at an arbitrary lattice site. These excitations explain the continuous crossover between the contrasting T≪$T_K$ and T≫$T_K$ behaviors. They also explain the surprisingly rapid weakening, with increasing T, of inelastic peaks in neutron scattering. The concept of ‘‘coherence’’ is clarified. Numerical results are presented for entropy, specific heat, average valence, magnetic susceptibility, and inelastic neutron scattering.