Kondo volume collapse and the γ→α transition in cerium

Abstract

The free energy stabilizing the Kondo singlet state is shown to be important in the total-energy and stability conditions for cerium and related solids. Explicit calculations are given for the simplest spin-1/2 Kondo model, using the relation to the Anderson Hamiltonian, which leads to a semiquantitative description of the γ→α phase transition in cerium. The temperature dependence of the free energy has a universal form which can lead to a phase boundary terminating in two critical points. © 1982 The American Physical Society.