Speaker
Urs Staub
(PSI)
Description
Ultrafast electron delocalization induced by a fs laser pulse is a well-known process in which electrons are ejected from the ions within the laser pulse duration.(1) However, the speed of electron localization on an atom by an excitation is unknown. Here, we demonstrate by means of x-ray absorption spectroscopy that an electron localization process into 4f states of a Eu-based correlated metal occurs within few-hundred femtoseconds. Our data suggests that the driving force for this process is either a reduction of the 4f states energy, a change of their bandwidth or an increase of the hybridization between the 4f/3d states. The observed ultrafast electron localization process raises fundamental questions for our understanding of electron correlations and their coupling to the lattice.
Primary author
Urs Staub
(PSI)