Electromagnetic dressing of the electron energy spectrum of Au(111) at high momenta
Marius Keunecke, Marcel Reutzel, David R. Schmitt, Alexander Osterkorn, Tridev Mishra, Christina Möller, Wiebke Bennecke, G. S. Matthijs Jansen, Daniel Steil, Salvatore R. Manmana, Sabine Steil, Stefan Kehrein, Stefan Mathias
Abstract
Light-engineering of quantum materials via electromagnetic dressing is considered an on-demand approach for tailoring electronic band dispersions and even inducing topological phase transitions. For probing such dressed bands, photoemission spectroscopy is an ideal tool, and we employ here a novel experiment based on ultrafast photoemission momentum microscopy. Using this setup, we measure the in-plane momentum-dependent intensity fingerprints of the electromagnetically-dressed sidebands from a Au(111) surface for $s$- and $p$-polarized infrared driving. We find that at metal surfaces, due to screening of the driving laser, the contribution from Floquet-Bloch bands is negligible, and the dressed bands are dominated by the laser-assisted photoelectric effect. Also, we find, from calculations, that in contrast to general expectations, $s$-polarized light can dress free-electron states at large photoelectron momenta. Our results show that the dielectric response of the material must carefully be taken into account when using photoemission for the identification of light-engineered electronic band structures.