Regensburg 2007 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 59: Oxides and Insulators: Clean Surfaces

O 59.1: Vortrag

Donnerstag, 29. März 2007, 15:45–16:00, H41

Structure of the (√67 × √67)R12.2^∘ surface oxide on Ni₃Al(111) — •Michael Schmid¹, Georg Kresse², Evelyn Napetschnig¹, and Peter Varga¹ — ¹Institut für Allgemeine Physik, TU Wien, Österreich — ²Institut für Materialpyhsik, Universität Wien, Österreich

With a unit cell size of 4.16 nm, the surface oxide on Ni₃Al(111) is one of the largest well-defined inorganic surface structures known today [1]. We have studied this oxide by high-resolution scanning tunneling microscopy (STM) and obtained atomic resolution of the topmost oxygen layer. This information, together with the building rules of the surface oxide on NiAl(110) [2] allowed us to build a raw model of the surface oxide, which was refined by density functional theory calculations. Although the structure is oxygen deficient, there are very few sites where the bonding environment of the individual atoms deviates from the rules found on NiAl(110). The most intriguing structural feature is a regular array of “holes” in the oxide, which explains the excellent properties of the structure as a template for growth of ordered arrays of clusters [3].

[1] S. Degen et al., Surf. Sci. 576, L57 (2005).

[2] G. Kresse et al., Science 308, 1440 (2005).

[3] G. Hamm et al., Nanotechnology 17, 1943 (2006).