Hamburg 2001 – scientific programme

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O: Oberflächenphysik

O 33: Methodisches (Experiment und Theorie)

O 33.13: Poster

Thursday, March 29, 2001, 18:30–18:45, M

Quantum-size effects in Double photoemission from metallic surface states. — •N. Fominykh, J. Berakdar, J. Henk, and P. Bruno — Max Planck Institut für Mikrostrukturphysik, Halle/Saale

This work focuses on the manifestation of quantum-size and correlation effects in double photoemission (DPE) spectra. The process under study is the simultaneous emission of two electrons upon the absorption of single VUV photon. The mathematical formulation of this process is an extention of the one-step model of single-electon photoemission (SPE) for the treatment of two correlation coupled time-reversed LEED states to represent the two emitted photoelectrons. The interaction between the two photoelectrons is modelled by a local wave-vector dependent effective one-particle potential. This framework has been realized in the previous works [1] and allows to reproduce the expected qualitative trends, in particular, the presence of the Coulomb correlation hole. In this work we investigate the DPE angular and energy distributions from the surface states of metals. By tuning the energies of the photon and detected electrons it is possible to probe a narrow initial state energy range, e.g. to select exactly the surface state region. Energetic and spatial localization of these states impose certain constraint on the DPE spectra, guided by the DPE energy and momentum concervation requirements. The complementary approach, which treats the quantum-well states in a simpler fashion and uses different model for electron-electron interaction, is demonstrated.

[1] N. Fominykh, J. Henk, J. Berakdar, P. Bruno, H. Gollisch, R. Feder, Sol.State Commun. 113, 665 (2000)