Probing high-energy final-state lifetimes with attosecond angle-resolved photoelectron spectroscopy

Photoelectron spectroscopy is one of the most important methods for extracting information about the material band structure. Final-state effects can complicate the interpretation of photoelectron data and these effects are challenging to address both experimentally and theoretically. In this work, we show that the attosecond pulse trains generated by high harmonic generation process in combination with interferometric time- and angle-resolve photoelectron spectroscopy enables a powerful tool (atto-ARPES) to directly access the final-state lifetimes in the time domain. Through our experiments on transition metals Cu(111) and Ni(111), we find the energy- and angle-dependent lifetime carries essential information about the bulk final states, which can serve as a sensitive probe for the final-state effects in solid-state photoemission.