Regensburg 2013 – scientific programme

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O: Fachverband Oberflächenphysik

O 10: Nanostructures at Surfaces I

O 10.2: Talk

Monday, March 11, 2013, 10:45–11:00, H45

First-principles investigation of monoatomic and dimer Mn adsorption on noble metal (111) surfaces — •Francisco Munoz^1,2, Aldo Romero², Jose Mejia-Lopez³, and Jose Luis Moran Lopez⁴ — ¹Martin-Luther-Universität Halle-Wittenberg, Halle, Germany — ²Max-Planck-Institut für Mikrostrukturphysik, Halle, Germany — ³Fac. de Fisica, Pontificia Universidad Catolica de Chile, Santiago, Chile — ⁴Dep. de Fisica, Fac. de Ciencias, UNAM, Mexico D. F., Mexico

A DFT-based investigation of the adsorption of Mn single atoms and dimers on the (111) surfaces of Cu, Ag, and Au is presented. The electronic structure of the Mn adatom, chemisorbed in all inequivalent surface geometries, is analyzed. For all three substrates, the most stable geometry is a Mn atom chemisorbed in a threefold coordinated site. For the dimer, the least-energy configuration corresponds to the molecule lying parallel to the surface. In this geometry, both atoms are chemisorbed in threefold coordinated sites, but with different local symmetry. It is also found that the magnetic ground-state configuration is an antiferromagnetic arrangement of the Mn atoms; however, for the Ag substrate, the ferromagnetic state is close in energy. Furthermore, the Mn₂ molecule is chemisorbed with very similar energy on various geometries. To study the dynamical motion of the dimer components, we calculated the potential energy barriers for the Mn motion at the various surfaces. We conclude that the Mn dimer moves relatively freely for Ag, in contrast to Cu and Au.