Attosecond streaking of photoelectron emission from disordered solids

TL;DR

This paper demonstrates the extension of attosecond streaking techniques to disordered solids like amorphous tungsten trioxide and polycrystalline gold, revealing electron transport dynamics on an attosecond timescale.

Contribution

It introduces a method to perform attosecond streaking on disordered solids, broadening the applicability of ultrafast electron dynamics measurements beyond crystalline materials.

Findings

Revealed near-field temporal structure at sample surfaces.

Observed photoelectron wavepacket broadening due to transport times.

Extended streaking techniques to amorphous and polycrystalline samples.

Abstract

Attosecond streaking of photoelectrons emitted by extreme ultraviolet light has begun to reveal how electrons behave during their transport within simple crystalline solids. Many sample types within nanoplasmonics, thin-film physics, and semiconductor physics, however, do not have a simple single crystal structure. The electron dynamics which underpin the optical response of plasmonic nanostructures and wide-bandgap semiconductors happen on an attosecond timescale. Measuring these dynamics using attosecond streaking will enable such systems to be specially tailored for applications in areas such as ultrafast opto-electronics. We show that streaking can be extended to this very general type of sample by presenting streaking measurements on an amorphous film of the wide-bandgap semiconductor tungsten trioxide, and on polycrystalline gold, a material that forms the basis of many nanoplasmonic devices. Our measurements reveal the near-field temporal structure at the sample surface, and photoelectron wavepacket temporal broadening consistent with a spread of electron transport times to the surface.