Electron-phonon coupling in photoemission spectra

Abstract

We present high-resolution photoemission data of the $\overline{\ensuremath{\Gamma}}$-surface state on Be(0001). Near the Fermi surface a narrow quasiparticle peak caused by strong electron-phonon coupling emerges. A many-body calculation is performed, which describes precisely the exceptional evolution of the experimental spectra. We demonstrate that all the necessary parameters can be directly deduced from the experiment.