Auger scattering channels are of fundamental importance to describe and understand the non-equilibrium charge carrier dynamics in graphene. While impact excitation increases the number of carriers in the conduction band and has been observed experimentally, direct access to its inverse process, Auger recombination, has so far been elusive. Here, we tackle this problem by applying our novel setup for ultrafast time-resolved photoelectron momentum microscopy. Our approach gives simultaneous access to charge carrier dynamics at all energies and in-plane momenta within the linearly dispersive Dirac cones. We thus provide direct evidence for Auger recombination on a sub-10~fs timescale by identifying transient energy- and momentum-dependent populations far above the excitation energy. We compare our results with model calculations of scattering processes in the Dirac cone to support our experimental findings.
Cite
@article{arxiv.2012.01256,
title = {Direct Access to Auger recombination in Graphene},
author = {Marius Keunecke and David Schmitt and Marcel Reutzel and Marius Weber and Christina Möller and G. S. Matthijs Jansen and Tridev A. Mishra and Alexander Osterkorn and Wiebke Bennecke and Klaus Pierz and Hans Werner Schumacher and Davood Momeni Pakdehi and Daniel Steil and Salvatore R. Manmana and Sabine Steil and Stefan Kehrein and Hans Christian Schneider and Stefan Mathias},
journal= {arXiv preprint arXiv:2012.01256},
year = {2020}
}