Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 85: Electron and spin dynamics I

O 85.5: Vortrag

Donnerstag, 17. März 2011, 17:30–17:45, WIL A317

Analysis of Si(001) 2PPE spectra obtained from ab initio simulations — •Henning Husser and Eckhard Pehlke — Institut für Theoretische Physik und Astrophysik, Universität Kiel, Germany

Two photon photoemission spectra have been calculated for the Si(001) surface by means of direct simulation of the time-dependent photocurrents. This work is motivated by experimental observations by Fauster et al. [1], Shudo and Munakata [2], and Kentsch et al. [3]. We present a series of spectra for both s- and p-polarized light and photon energies in the range of 2.8 – 4.8 eV. Time-dependent excitation spectra are derived approximately by projection of the time-dependent wavefunctions onto the Kohn-Sham eigenstates in order to investigate the dynamics of the photoemission process. The selection rules for the 2PPE process will be compared to the selection rules for 1PPE. In order to explore the possibility of surface resonances which might lead to an enhancement of the photoemission intensity in particular from the dangling bond state, we have calculated the projected density of states at the Si(001) surface in the energy range of the intermediate states.

[1] T. Fauster, S. Tanaka, K. Tanimura, Verhandl. DPG (VI) 45, 3/544 (2010). [2] K. Shudo and T. Munakata, Phys. Rev. B 63, 125324 (2001). [3] C. Kentsch, M. Kutschera, M. Weinelt, Th. Fauster, M. Rohlfing, Phys. Rev. B 65, 035323 (2002).