Observation of Real-Space Dynamic Electron Correlation in Beryllium

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 Å, consistent with theoretical expectations. However, at the plasmon energy of ~21 eV, the exchange-correlation hole is extended up to 4-5 Å, suggesting a unique influence of the dynamic plasmon state.