Observation of Real-Space Dynamic Electron Correlation in Beryllium

TL;DR

This study provides the first direct real-space experimental measurement of dynamic electron correlation in beryllium, revealing the size and extension of the exchange-correlation hole and its relation to plasmon states.

Contribution

It introduces a novel inelastic X-ray scattering method to measure dynamic electron correlation directly in real space, confirming theoretical predictions and revealing new insights.

Findings

Exchange-correlation hole size is ~2 Å.

At plasmon energy, the hole extends up to 4-5 Å.

Results align with and extend theoretical models.

Abstract

Electron correlation in solid has a major impact on material properties. However, it has been studied mainly by theory, with very limited direct experimental investigations. Here, we report the results of real-space measurement of dynamic electron correlation using inelastic X-ray scattering on polycrystalline beryllium. The data are expressed as the energy-resolved dynamic pair-distribution function. Our results confirm the size of the exchange-correlation hole as ~2 {\AA}, consistent with theoretical expectations. However, at the plasmon energy of ~21 eV, the exchange-correlation hole is extended up to 4-5 {\AA}, suggesting a unique influence of the dynamic plasmon state.