Interplay between Heavy Fermions and Crystal Field Excitation in Kondo Lattices. Low-Temperature Thermodynamics and Inelastic Neutron Scattering Spectra of CeNiSn

TL;DR

This paper develops a microscopic theory describing how heavy fermions interact with crystal field excitations in Kondo lattices, explaining experimental spectra and thermodynamics of CeNiSn at low temperatures.

Contribution

It introduces a detailed theoretical framework showing how crystal field excitations modify the heavy-fermion spectrum when their energy is below the Kondo temperature.

Findings

The theory explains anisotropic inelastic neutron scattering spectra.

It accounts for the low-temperature specific heat behavior.

Resolves contradictions between metallic conductivity and thermodynamic properties.

Abstract

The microscopic theory of interaction between the heavy fermions and the crystal field excitations in Kondo lattices is presented. It is shown that the heavy-fermion spectrum scaled by the Kondo temperature $T_K$ can be modified by the crystal field excitations with the energy $\Delta_{CF}$ provided the inequality $\Delta_{CF}<T_K$ is realized. On the base of general description of excitation spectrum the detailed qualitative and quantitative explanation of anisotropic inelastic neutron scattering spectra and low-temperature specific heat of orthorhombic CeNiSn is given. The theory resolves the apparent contradiction between the metallic conductivity and the gap-wise behavior of thermodynamic properties and spin response of CeNiSn at low temperatures.