Mean-field expression for the characteristic Grüneisen parameter of the Kondo lattice.

Abstract

In addition to the enhanced specific heat coefficient and susceptibility, heavy fermion compounds also exhibit a large characteristic Gr\uneisen parameter (\ensuremath{\Gamma}) for different properties. We clarify the relevant intrinsic energy scale in the presence of a magnetic field, and derive the analytic expression for \ensuremath{\Gamma} by use of the slave-boson mean-field results. Our results are at variance with the belief that \ensuremath{\Gamma} is proportional to the enhancement of the quasiparticle mass. We find instead that, besides the contribution from the sensitive volume dependence of the hybridization matrix element, \ensuremath{\Gamma} roughly depends on the logarithm of the mass enhancement.