Berlin 2015 – scientific programme
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O: Fachverband Oberflächenphysik
O 73: Nanostructures at Surfaces: 1D and 2D Structures
O 73.9: Poster
Wednesday, March 18, 2015, 18:15–21:00, Poster A
Effect of electron-phonon coupling on band-structure formation: Chains of Cl-vacancies — Bruno Schuler1, Mats Persson2, Sami Paavilainen3, •Niko Pavliček1, Leo Gross1, Gerhard Meyer1, and Jascha Repp4 — 1IBM Research–Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland — 2Science Research Centre, University of Liverpool, L69 3BX, United Kingdom — 3Department of Physics, Tampere University of Technology, 33720 Tampere, Finland — 4Institute of Experimental and Applied Physics, University of Regensburg, 93053 Regensburg, Germany
We have investigated the effects of strong electron-phonon (e-ph) coupling on the formation of extended electronic states of Cl divacancies and vacancy chains in a NaCl bilayer on Cu(111) with scanning tunneling spectroscopy, atomic force microscopy and a tight-binding model including linear coupling to phonon modes. Vacancy pairs and chains with different orientation and separation were created by extracting individual Cl anions with atomic precision using vertical manipulation. Symmetric and anti-symmetric vacancy states (VS) and localized interface states are shown to be formed at divacancies, in analogy with the bonding and anti-bonding orbitals of the hydrogen molecule. As expected, the level splitting increases with decreasing inter-vacancy distance. However, splitting of the VSs is significantly enlarged by level repulsion as a result of the strong e-ph interaction [1]. Already for chains of a few coupled vacancies we observe an emerging band structure of the defect band.
[1] J. Repp, et al., Phys. Rev. Lett. 95, 225503 (2005).