The alpha-gamma transition of Cerium is entropy-driven

TL;DR

This paper demonstrates that the alpha-gamma transition in cerium is primarily driven by entropy, supported by experimental data and advanced theoretical calculations including dynamical mean-field theory.

Contribution

It introduces a new implementation of dynamical mean-field theory that includes semi-core states, providing detailed insights into the entropy-driven transition in cerium.

Findings

The gamma-phase is entropically stabilized over a wide temperature range.

The transition involves a stabilization energy of the alpha phase linked to Kondo resonance development.

Results align with experimental energy differences and the entropy-driven transition model.

Abstract

We emphasize, on the basis of experimental data and theoretical calculations, that the entropic stabilization of the gamma-phase is the main driving force of the alpha-gamma transition of cerium in a wide temperature range below the critical point. Using a formulation of the total energy as a functional of the local density and of the f-orbital local Green's functions, we perform dynamical mean-field theory calculations within a new implementation based on the multiple LMTO method, which allows to include semi-core states. Our results are consistent with the experimental energy differences and with the qualitative picture of an entropy-driven transition, while also confirming the appearance of a stabilization energy of the alpha phase as the quasiparticle Kondo resonance develops.