Effect of thermal vibration and the solid-liquid phase transition on electron dynamics: An inelastic x-ray-scattering study on Al

Abstract

Inelastic-x-ray-scattering measurements of the dynamic structure factor, $S(q,\ensuremath{\omega}),$ of electrons in Al both in the solid phase at rising temperatures and in the liquid are presented. The double-peak structure of $S(q,\ensuremath{\omega})$ for $q>{q}_{c}$ (${q}_{c}=$plasmon cutoff vector), diminishes gradually with decreasing strength of the ion-core potential; the peak position and the sloping plateau of the $S(q,\ensuremath{\omega})$ spectra for $q>{q}_{c}$ do not exhibit marked changes upon melting. The plasmon energy for $q<{q}_{c}$ shifts according to the variation of the electron density upon heating and melting, and does not respond to the loss of long-range order.