We present an electron projection imaging method to study the ultrafast evolution of photoelectron density distribution and transient fields near the surface. The dynamical profile of the photoelectrons from graphite reveals an origin of a thermionic emission, followed by an adiabatic process leading to electron acceleration and cooling before a freely expanding cloud is established. The hot electron emission is found to couple with a surface charge dipole layer formation, with a sheet density several orders of magnitude higher than that of the vacuum emitted cloud.
@article{arxiv.0910.4422,
title = {Ultrafast imaging of photoelectron packets generated from graphite surface},
author = {Ramani K. Raman and Zhensheng Tao and Tzong-Ru Han and Chong-Yu Ruan},
journal= {arXiv preprint arXiv:0910.4422},
year = {2015}
}
Comments
9 pages, 4 figures. Applied Physics Letter, in press