Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 59: Metal Substrates I
O 59.12: Vortrag
Mittwoch, 2. April 2014, 18:45–19:00, WIL A317
Lateral Segregation in Pt50Rh50(111) induced by a h-BN nanomesh — •Roland Stania1, Irakli Kalichava1, Bernd Schönfeld2, Jürg Osterwalder1, Wolfgang Heckel3, Tobias C. Kerscher3, Stefan Müller3, Philip R. Willmott1, and Thomas Greber1 — 1Universität Zürich, Physik-Institut — 2ETH Zürich, LMPT — 3Hamburg University of Technology, Institute of Advanced Ceramics
Epitaxially grown hexagonal boron nitride (h-BN) on Rh(111) forms a corrugated monolayer with a 13 on 12 super-honeycomb-structure known as the h-BN nanomesh [1]. In contrast h-BN on Pt(111) forms a flat layer with an approximate 10 on 9 superstructure being weaker bonded than the nanomesh [2]. The investigation of h-BN/Pt50Rh50(111) reveals a corrugated nanomesh-like 11 on 10 superstructure with a periodicity of 2.8 nm. Lateral segregation occurs in the topmost layer of the substrate during growth of h-BN, where Rh atoms form islands under the pores of the nanomesh which are surrounded by Pt atoms under the wires. The unit cell size is obtained by surface X-ray diffraction, while angular resolved photoemission indicates the nanomesh structure and the lateral segregation. The picture of lateral segregation at the nanometer scale is perfectly confirmed by density functional theory within a cluster expansion approach.
[1] Corso et al. Science 303 (2004) 217.
[2] Ćavar et al. Surface Science 602 (2008) 1722.