# The Transition from Heavy Fermion to Mixed Valence in Ce1-xYxAl3: A Quantitative Comparison with the Anderson Impurity Model

## TL;DR

This study investigates the transition from heavy-fermion to mixed-valence states in Ce1-xYxAl3 using neutron scattering, demonstrating that increased hybridization shifts spectral weight to higher energies, aligning with Anderson impurity model predictions.

## Contribution

It provides a quantitative comparison of experimental neutron scattering data with the Anderson impurity model across the transition.

## Key findings

- Hybridization increases with Y doping, raising the Kondo temperature.
- Spectral weight shifts to high energy with increased hybridization.
- The Anderson impurity model accurately describes the transition.

## Abstract

We present a neutron scattering investigation of Ce1-xYxAl3 as a function of chemical pressure, which induces a transition from heavy-fermion behavior in CeAl3 (TK=5 K) to a mixed-valence state at x=0.5 (TK=150 K). The crossover can be modeled accurately on an absolute intensity scale by an increase in the k-f hybridization, Vkf, within the Anderson impurity model. Surprisingly, the principal effect of the increasing Vkf is not to broaden the low-energy components of the dynamic magnetic susceptibility but to transfer spectral weight to high energy.