Theory of an elastic anomaly in the heavy fermion system CeTe

TL;DR

This paper models the elastic anomaly in CeTe's heavy fermion system using the Anderson lattice model, explaining temperature-dependent elastic constants and the observed dip through coupling between strain and crystal field splitting.

Contribution

It introduces a theoretical framework that accounts for elastic anomalies in CeTe by considering crystal field effects and elastic strain interactions within the Anderson lattice model.

Findings

The model reproduces the temperature dependence of elastic constants in CeTe.

The downward dip in elastic constants is explained by coupling with $ ext{Gamma}_8$ quartet splitting.

The theory aligns well with experimental data on CeTe's elastic behavior.

Abstract

The elastic anomaly observed in the coherent Kondo state of Ce heavy fermion compounds is analyzed by using the Anderson lattice model simulating the energy level scheme of CeTe. The $\Gamma_7$ doublets and $\Gamma_8$ quartets of the 4f states are considered in the model. We solve the mean field equations to derive the temperature dependences of elastic constants, using the random phase approximation like expression for the interaction between the elastic strain and the crystalline field splitting. We compare the calculation with the $(c_{11} - c_{12})/2$ and $c_{44}$ constants of CeTe. The presence of the downward dip and the observed overall temperature variations of the two constants are well described by the present theory. The origin of the dip is the coupling between the elastic strain and the splitting of the $\Gamma_8$ quartets.