Attosecond electron dynamics on solid surfaces

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This project will explore the measurement and control of ultrafast photo-excitation of solids. The goal is to obtain new insight into the dynamics of photoelectrons near the surfaces of solids on the attosecond time-scale and atomic length scale. These dynamics involve a number of complex and interconnected phenomena that are currently not well understood, but are fundamental to the function of current and future nanoscale quantum devices, solar cells, sensors and the catalytic action of surfaces. Some of the relevant processes and their characteristic timescales are: thermalisation of hot electrons at the Fermi edge (10s of fs), transport time for electron from delocalised and localised core-states to surface (<1fs), charge transfer of electrons from adsorbed atom to substrate (<1fs), charge screening and image charge creation (<1fs), direct and indirect electron scattering in clusters (<1fs to fs). Key questions that this project will address include:(i) How do photoelectron wavepackets launched inside a metal or semiconductor propagate to the surface and on what timescales? (ii) How are the photo-excitation and electron wavepacket propagation modified by adsorbate layers? (iii) Can photoelectron emission and photocurrents from surfaces be controlled on the nanoscale and on the few femtosecond to attosecond timescales by tailoring both samples and optical waveforms?