Femtosecond dynamics of hot-electron relaxation in Cu(110) and Cu(100)

Abstract

Hot-electron relaxation dynamics due to electron-electron scattering at Cu(110) and Cu(100) surfaces are measured with < 10 fs time resolution by two-photon time-resolved photoemission spectroscopy. Comparison of experimental population decay rates for hot electrons with 1.3-3.2 eV energy above the Fermi level with those calculated by the Fermi liquid theory shows significant disagreement. The experimental rates are on average ∼ 5 times slower, have a different energy dependence than predicted by theory, and depend on the crystal face of Cu. The time scales for hot-electron thermalization measured here are important for understanding and controlling hot-electron-induced chemistry at metal surfaces.