Angle resolved Photoemission from Ag and Au single crystals: Final state lifetimes in the as range

TL;DR

This study investigates the final state lifetimes in Ag(111) and Au(111) single crystals using angle-resolved photoemission spectroscopy across a broad photon energy range, revealing attosecond-scale electron lifetimes.

Contribution

It provides new insights into final state lifetimes in noble metal crystals using photoemission spectra, offering an alternative to laser spectroscopy methods.

Findings

Final states are f-derived, 16-17 eV above EF.

Electron lifetimes are in the attosecond range.

Distinct resonance phenomena observed.

Abstract

We present angle resolved photoemission spectra for Ag(111) and Au(111) single crystals in normal emission geometry, taken at closely spaced intervals for photon energies between 8 eV and 160 eV. The most dominant transitions observed are attributed to f-derived final states located about 16 eV to 17 eV above EF for both materials. These transitions exhibit very distinct resonance phenomena and selection rules and are reminiscent of the angular momentum characteristics of the states involved. The excited electron lifetime is in the attosecond (as) range as determined from the energy width of the observed transitions. This serves as an alternate approach to the direct determination of excited electron lifetimes by as laser spectroscopy.