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O: Fachverband Oberflächenphysik
O 65: Methods: Theory and Experiment
O 65.3: Vortrag
Donnerstag, 28. Februar 2008, 12:30–12:45, MA 141
Anisotropic electron-phonon coupling strength at the Be(0001) surface — M. Fuglsang Jensen1, •E. D. L. Rienks1, T.-Y. Chien2, I. Yu. Sklyadneva3, A. Eiguren3, P. M. Echenique3, E. V. Chulkov3, E. W. Plummer2, and Ph. Hofmann1 — 1Institute for Storage Ring Facilities, University of Aarhus, Århus, Denmark — 2Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee, USA — 3Donostia International Physics Center, San Sebastian, Basque Country, Spain
Electronic surface states are useful model systems for understanding many-body effects in solids, such as electron-phonon coupling (EPC). Advances in angle-resolved photoemission spectroscopy not only allow one to assess the strength of the EPC, but also enable experimental determination of the Eliashberg function, that fully characterizes the electron phonon coupling in a given system.
Although the electronic structure of the Be(0001) surface is well studied, there is no agreement on the strength of the EPC at this surface. This strength is described by the mass enhancement parameter λ. An anisotropic coupling might account for this discrepancy, as these results are obtained along different crystal directions.
This study is aimed at obtaining a full description of EPC at this surface. Experimentally, the Eliashberg function (and λ) can be determined from the renomalized dispersion of the Γ surface state at the Fermi energy crossing. Preliminary results show that there is indeed a substantial variation of λ between the Γ M and the Γ K directions. The same trend is observed in a first principles study of this system.