We investigate the temporal evolution of the electronic states at the bismuth (111) surface by means of time and angle resolved photoelectron spectroscopy. The binding energy of bulk-like bands oscillates with the frequency of the A1g phonon mode whereas surface states are insensitive to the coherent displacement of the lattice. A strong dependence of the oscillation amplitude on the electronic wavevector is correctly reproduced by \textit{ab initio} calculations of electron-phonon coupling. Besides these oscillations, all the electronic states also display a photoinduced shift towards higher binding energy whose dynamics follows the evolution of the electronic temperature.
@article{arxiv.1112.3949,
title = {Coherent Phonon Coupling to Individual Bloch States in Photoexcited Bismuth},
author = {E. Papalazarou and J. Faure and J. Mauchain and M. Marsi and A. Taleb-Ibrahimi and I. Reshetnyak and A. van Roekeghem and I. Timrov and N. Vast and B. Arnaud and L. Perfetti},
journal= {arXiv preprint arXiv:1112.3949},
year = {2012}
}