Femtosecond-Time-Resolved Surface Structural Dynamics of Optically Excited Silicon

Abstract

The dynamics of the structural changes that take place on a silicon surface following excitation with an intense optical pulse are observed with 90-fs time resolution. The threefold rotational symmetry of the silicon $〈111〉$ surface becomes rotationally isotropic within a picosecond after excitation consistent with a transition from the crystalline to the liquid molten state.