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O: Fachverband Oberflächenphysik

O 31: Clean surfaces II

O 31.7: Vortrag

Dienstag, 27. März 2012, 12:00–12:15, A 060

Ultra-thin ZnO films on metal substrates from first principle — •Bjoern Bieniek, Yong Xu, Patrick Rinke, and Matthias Scheffler — Fritz Haber Institut der MPG, Berlin, Germany

In the context of hybrid inorganic/organic interfaces, ZnO is becoming more and more wide spread as inorganic component. To prevent charging or conductivity problems in surface sensitive characterization techniques such as scanning tunneling microscopy or photoemission spectroscopy, metal supported ultra-thin ZnO films can be used as model systems. By means of PBE density-functional theory (DFT) calculations we investigate to what extend ultra-thin ZnO on the (111) surfaces of Ag, Cu and Pd resembles the properties of bulk ZnO surfaces or if it should be regarded as a distinct nanosystem in its own right [1]. Free standing ZnO mono-layer thin films deviate from the wurtzite structure of the bulk material and adopt a planar, graphite-like geometry, in agreement with previous calculations [2]. By inspecting the stress/strain curve of the freestanding mono-layer the expected commensurability condition for different substrates can be estimated. The PBE calculations reveal that the ZnO/metal interaction is weak and a 8 x 9 reconstruction on Ag (111) is most stable [3]. The results will be analyzed in terms of the underlying electronic structure and the effect of the exchange-correlation functional and the thickness of the ZnO layers will be addressed. [1] C. Freysoldt et al., Phys. Rev. Lett. 99, 086101 (2007), [2] Z. C. Tu and X. Hu, Phys. Rev. B 74, 035434 (2006), [3] C. Tusche et al., Phys. Rev. Lett. 99, 026102 (2007)