Dresden 2017 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 100: Electronic Structure of Surfaces: Spectroscopy, Surface States II

O 100.10: Vortrag

Donnerstag, 23. März 2017, 18:15–18:30, WIL C307

Double photoemission from transition metal surfaces — •Ilya Kostanovskiy, Yuri Aliaev, Gianluca Di Filippo, Jürgen Kirschner, and Frank O. Schumann — Max-Planck-Institut für Mikrostrukturphysik, Halle, Germany

The evolution of the 4p photoemission spectra for the 4th group transition metals exhibits large line width. This is assigned to the breakdown of the one-electron picture and electron-electron interaction.[1] Photoemission from the 4p level is accompanied by the Auger decay resulting in the final state with two holes in the 4d level. The process of the Auger-photoelectron double photoemission (DPE) can be studies via coincidence photoemission technique. Recent studies of the DPE spectra of Pd and Ag revealed clear evidence of the attosecond dynamics of the 4p photoemission process.[2]

We studied the DPE process involving the 3d and 4p levels from Cd, In, Sn and Sb surfaces. In contrast to the Pd case, the 4d state of these materials is not part of the valence band but a core level. We measured 2D energy distributions of DPE process and plotted the sum energy shape of the Auger-photoelectron pairs. We discuss the 2D energy distributions in terms of ultrafast electron dynamics of the Auger-photoelectron pair emission. The sum energy plots of the 4p and 3d DPE spectrum are very similar despite the very different timescales.