We demonstrate the contribution of coherent excitation pathways in three-photon photoemission from Cu(001). We identify separate peaks in the photoelectron spectra as originating from two specific Cud bands that are excited at different k points via the same unoccupied image-potential state. By model calculations we show that our experimental observations impose lower limits on the relevant Cud -hole dephasing time on the order of 10-20 fs. Our findings suggest extensions to future studies in electronic structure mapping with tunable laboratory and free-electron laser sources, exploiting possible multiphoton resonances between occupied bulk and unoccupied surface states.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2009 Oct 20|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics