Thermodynamics of the $\alpha$-$\gamma$ transition in cerium studied by an LDA + Gutzwiller method

TL;DR

This study uses advanced first-principles calculations to analyze the thermodynamics of cerium's alpha-gamma phase transition, revealing the importance of electronic and lattice entropy in the transition and accurately reproducing experimental phase diagrams.

Contribution

The paper applies LDA + Gutzwiller density functional theory to comprehensively study cerium's phase transition, including entropy effects, and achieves excellent agreement with experimental data.

Findings

First order transition persists to zero temperature with negative pressure

Electronic and lattice vibrational entropy are crucial for the transition

Calculated phase diagram matches experimental results

Abstract

The $\alpha$-$\gamma$ transition in cerium has been studied in both zero and finite temperature by Gutzwiller density functional theory. We find that the first order transition between $\alpha$ and $\gamma$ phases persists to the zero temperature with negative pressure. By further including the entropy contributed by both electronic quasi-particles and lattice vibration, we obtain the total free energy at given volume and temperature, from which we obtain the $\alpha$-$\gamma$ transition from the first principle calculation. We also computed the phase diagram and pressure versus volume isotherms of cerium at finite temperature and pressure, finding excellent agreement with the experiments. Our calculation indicate that both the electronic entropy and lattice vibration entropy plays important role in the $\alpha$-$\gamma$ transition.