Regensburg 2010 – scientific programme
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O: Fachverband Oberflächenphysik
O 41: Poster Session I (Semiconductor Substrates: Epitaxy and growth; Semiconductor Substrates: Adsorbtion; Semiconductor Substrates: Solid-liquid interfaces; Semiconductor Substrates: Clean surfaces; Oxides and insulators: Epitaxy and growth; Oxides and insulators: Adsorption; Oxides and insulators: Clean surfaces; Organic, polymeric and biomolecular films - also with adsorbates; Organic electronics and photovoltaics, Surface chemical reactions; Heterogeneous catalysis; Phase transitions; Particles and clusters; Surface dynamics; Surface or interface magnetism; Electron and spin dynamics; Spin-Orbit Interaction at Surfaces; Electronic structure; Nanotribology; Solid/liquid interfaces; Graphene; Others)
O 41.27: Poster
Tuesday, March 23, 2010, 18:30–21:00, Poster B1
Tunneling Spectroscopy of Cl Divacancies in Ultrathin NaCl Films — •Jascha Repp1, Gerhard Meyer2, Sami Paavilainen3, Fredrik Olsson4, and Mats Persson5 — 1Institute of Experimental and Applied Physics, University of Regensburg, 93040 Regensburg, Germany — 2IBM Research - Zurich, 8803 Rüschlikon, Switzerland — 3Institute of Physics, Tampere University of Technology, 33720 Tampere, Finland — 4Department of Applied Physics, Chalmers University, 41296 Göteborg, Sweden — 5Surface Science Research Centre and Department of Chemistry, The University of Liverpool, Liverpool, L69 3BX, United Kingdom
In recent years, ultrathin insulating films on metal substrates have gained appreciable attention as templates for the study of individual adsorbates. Cl-vacancies in NaCl films on copper substrates exhibit an unoccupied state localized directly at the vacancy. In this work we study pairs of Cl vacancies in NaCl layers on copper substrates with mutual distances ranging from ∼4 Å to ∼12 Å by means of scanning tunneling spectroscopy and density functional theory. The close vicinity of these vacancies results in an coupling of the electronic states associated with the individual vacancies. The unoccupied states located directly at the vacancies couple and form a symmetric and an antisymmetric state in analogy to the bonding and antibonding states in a hydrogen molecule. Theoretical analysis shows that the energy splitting of these states is appreciably increased by the zero-point fluctuations of the phonons in the polar insulator.