Crystal Field in Kondo System

Abstract

We present a theory for calculating the crystal field effects in Kondo systems of Ce compounds and alloys. By extending Abrikosov’s pseudofermion method, the static and dynamical susceptibilities are formulated as functions of the self-energy of the pseudofermions. The self-energy is self-consistently treated in the ladder approximation. It is shown that the crystal field is not constant but depends on temperature through the renormalization of the exchange interaction between Ce³⁺ ions and conduction electrons. The neutron quasi-elastic and inelastic scattering spectra and the static susceptibility are in good agreement with the experimental ones in the cubic Kondo system, Ce_xLa_1−xAl₂. This agreement suggests that the present theory is applicable to many materials.