Probing the gamma-alpha Transition in Bulk Ce under Pressure: A Direct Investigation by Resonant Inelastic X-ray Scattering

TL;DR

This study uses resonant inelastic x-ray scattering to directly investigate the changes in 4f-electron properties of elemental cerium during the gamma-alpha transition under pressure, revealing band formation and increased Kondo screening.

Contribution

It provides the most comprehensive bulk measurement of 4f-electron behavior across the gamma-alpha transition in cerium using RIXS and theoretical modeling.

Findings

4f-electron occupation number decreases in the alpha phase

Band formation of 4f electrons is observed under pressure

Reduced electron correlation and enhanced Kondo screening at high pressure

Abstract

We report on the most complete investigation to date of the 4f-electron properties at the gamma-alpha transition in elemental Ce by resonant inelastic x-ray scattering (RIXS). The Ce 2p3d-RIXS spectra were measured directly in the bulk material as a function of pressure through the transition. The spectra were simulated within the Anderson impurity model. The occupation number nf was derived from the calculations in both gamma- and alpha-phases in the ground state along with the f doubleoccupancy. We find that the electronic structure changes result mainly from band formation of 4f electrons which concurs with reduced electron correlation and increased Kondo screening at high pressure.