title: Negatively charged ions on Mg(0001) surfaces: appearance and origin of attractive adsorbate-adsorbate interactions.
abstract: Adsorption of electronegative elements on a metal surface usually leads to an increase in the work function and decrease in the binding energy as the adsorbate coverage rises. Using density-functional theory calculations, we show that Cl adsorbed on a Mg(0001) surface complies with these expectations, but adsorption of {N,O,F} causes a decrease in the work function and an increase in the binding energy. Analyzing the electronic structure, we show that the presence of a highly polarizable electron spill-out in front of Mg(0001) causes this unusual adsorption behavior and is responsible for the appearance of a hitherto unknown net-attractive lateral electrostatic interaction between same charged adsorbates.
authors.affiliation: Department for Computational Materials Science, Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Strasse 1, D-40237 Düsseldorf, Germany.
authors.forename: Su-Ting
authors.initials: ST
authors.lastname: Cheng
authors.affiliation: Department for Computational Materials Science, Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Strasse 1, D-40237 Düsseldorf, Germany.
authors.forename: Mira
authors.initials: M
authors.lastname: Todorova
authors.affiliation: Department for Computational Materials Science, Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Strasse 1, D-40237 Düsseldorf, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Freysoldt
authors.affiliation: Department for Computational Materials Science, Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Strasse 1, D-40237 Düsseldorf, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Neugebauer