Berlin 2015 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 96: Ultrafast Electron Dynamics at Surfaces and Interfaces

O 96.4: Vortrag

Freitag, 20. März 2015, 11:30–11:45, MA 004

One-step theory of pump-probe photoemission — •Jürgen Braun¹, Roman Rausch², Michael Potthoff², Jan Minàr¹, and Hubert Ebert¹ — ¹Dept. Chemie, LMU Universität München, Germany — ²I. Institut für Theoretische Physik, Universität Hamburg, Germany

A theoretical frame for the description of pump-probe photoemission is presented. The approach is based on a general formulation using the Keldysh formalism for the lesser Green function to describe the real-time evolution of the electronic degrees of freedom in the initial state after a strong pump pulse that drives the system out of equilibrium. The final state is represented by a time-reversed low-energy electron diffraction (LEED) state. Our one-step description is related to Pendry's original formulation of the photoemission process as close as possible. The formalism allows for a quantitative calculation of the time-dependent photocurrent in particular for simple metals where a picture of effectively independent electrons is assumed as reliable. The theory is worked out for valence- and core-electron excitations [1]. As a first application, the theoretical description of two-photon photoemission for real systems within the KKR-approach is introduced [2].

1. J. Braun, R. Rausch, M. Potthoff, J. Minàr, H. Ebert, submitted to Phys. Rev. B (2014)

2. H. Ebert et al., The Munich SPR-KKR package, version 6.3, http://olymp.cup.uni-muenchen.de/ak/ebert/SPRKKR (2012)