Abstract
Transient changes of the complex self-energy of the surface state on Gd(0001) after intense optical excitation are investigated by femtosecond time-resolved photoemission. We observe an ultrafast () broadening of the linewidth due to scattering followed by a decrease of the binding energy due to thermal expansion of the lattice. In addition, we resolve a periodic breathing of the band structure which originates from a coherent phonon. An amplitude of 1 pm is derived from the binding energy shift upon lattice displacement calculated by density functional theory.
- Received 6 July 2006
DOI:https://doi.org/10.1103/PhysRevLett.98.097401
©2007 American Physical Society