The Gutzwiller approach to magnetic instabilities in heavy-fermion systems

Abstract

Magnetic properties of the orbitally nondegenerate periodic Anderson model are investigated using Kotliar and Ruckenstein's slave-boson reformulation of the Gutzwiller variational method (1986). The Gutzwiller approximation is reproduced at the saddle-point level for T=0. This approach allows one to extend the analysis of Rice and Ueda (1985) to calculate the magnetization as a function of applied magnetic field. The authors find that a magnetic instability exists in the Kondo regime. The findings suggest that the Gutzwiller approximation is too biased towards the magnetic state.