<title>Femtosecond dynamics of hot electrons at clean Cu(110) and Cu(100) surfaces</title>

Abstract

Hot-electron thermalization by electron-electron scattering is measured by two-photon photoemission spectroscopy at clean Cu(110) and Cu(100) surfaces. Two-photon photoemission spectra are measured as a function crystal face, laser polarization, and photon energy to establish the excitation mechanism. Time-resolved measurements of hot-electrons dynamics using approximately 3.2 eV femtosecond laser excitation light show a two- component decay due to dephasing and population relaxation dynamics. Hot-electron lifetimes in the 1.3 - 3.3 eV energy range decrease from approximately 80 fs to approximately 15 fs as the energy is increased. Energy dependence of the population decay rate is approximately 6.5 times slower than predicted by the Fermi liquid theory and shows a modest dependence on the Cu crystal face. Observation of hot-electron coherence on <EQ 15 fs time scale opens the way for coherent control of hot-electron induced dynamics at metal interfaces by ultrafast lasers.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.