%0 Journal Article
%A Krasovskii, E. E.
%A Friedrich, Christoph
%A Schattke, W.
%A Echenique, P. M.
%T Rapid propagation of a Bloch wave packet excited by a femtosecond ultraviolet pulse
%J Physical review / B
%V 94
%N 19
%@ 2469-9950
%C Woodbury, NY
%I Inst.
%M FZJ-2016-07499
%P 195434
%D 2016
%X Attosecond streaking spectroscopy of solids provides direct observation of the dynamics of electron excitation and transport through the surface. We demonstrate the crucial role of the exciting field in electron propagation and establish that the lattice scattering of the outgoing electron during the optical pumping leads to the wave packet moving faster than with the group velocity and faster than the free electron. We solve the time-dependent Schrödinger equation for a model of laser-assisted photoemission, with inelastic scattering treated as electron absorption and alternatively by means of random collisions. For a weak lattice scattering, the phenomenological result that the photoelectron moves with the group velocity dE/dℏk and traverses on average the distance equal to the mean-free path is proved to hold even at very short traveling times. This offers a novel interpretation of the delay time in streaking experiment and sheds new light on tunneling in optoelectronic devices.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000388465800004
%R 10.1103/PhysRevB.94.195434
%U https://juser.fz-juelich.de/record/825003