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O: Fachverband Oberflächenphysik
O 14: Metal Substrates: Epitaxy and Growth
O 14.3: Vortrag
Montag, 26. März 2007, 14:45–15:00, H39
Surface state mediated atomic-string and superlattice — •Haifeng Ding1,2, Chunlei Gao1, Marta Waśniowska1, Nikolay Negulyaev1, Larissa Niebergall1, Valeriy Stepanyuk1, Patrick Bruno1, and Jürgen Kirschner1 — 1Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, Halle, 06120, Germany — 2National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing, 210093, China
We present a joint experimental and theoretical study of Fe atoms alignment on a flat and a vicinal Cu(111) surface. A few percent monolayer of Fe atoms are deposited at around 5 K on a clean Cu(111)surface. Upon deposition, the Fe atoms are randomly distributed on the sample surface without apparent ordering. With annealing to 13 K, the Fe atoms form ordered structures on both flat and vicinal surfaces. On the flat surfaces, hexagonal superlattice with nearest neighbor distance of 1.2±0.1 nm is found. On the vicinal surfaces, we find the Fe atoms form a string like structure along the step edges. The Fe atoms also have the same nearest neighbor distance as the superlattice and they have a fixed separation of 0.8±0.1 nm away from the step edges. Together with the first principle calculation and Monte-Carlo simulations, our findings evidence that the surface state can mediate atom diffusion, resulting the formation of atomic string and superlattice.