Dresden 2009 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 53: Nanostructures at surfaces: Dots, particles, clusters III
O 53.3: Vortrag
Donnerstag, 26. März 2009, 15:30–15:45, SCH A215
X-ray evidence for mesoscopic relaxations in Cobalt nanoislands on Cu(001) — Oleg Mironets1, •Holger L. Meyerheim1, Christian Tusche1, Valery S. Stepanyuk1, Eelena Soyka1, Paul Zschack2, Hawoong Hong2, Nicole Jeutter3, Roberto Felici3, and Jürgen Kirschner1 — 1MPI f. Mikrostrukturphysik, D-06120 Halle (Germany) — 2APS, Argonne National Laboratory, Argonne, IL 60439 (USA) — 3ESRF, F-38043 Grenoble (France)
Surface x-ray diffraction (SXRD) combined with scanning unneling microsocopy (STM) and molecular dynamics (MD) calculations provides evidence that monolayer thick Co nanoislands on Cu(001) experience large relaxations called mesoscopic misfit (MM). In small Co islands consisting of several tens of atoms only, the average bond length is reduced to 2.40-2.45 Å (bulk: 2.51 Å). The SXRD analysis is based on the determination of the Co-adlayer position on Cu(001) by probing the intensity distribution along the crystal truncation rods [1]. In contrast to the case of large islands (>>100 atoms), where Co-atoms reside in hollow sites separated by 2.56 Å, Co-atoms in mesoscopic misfitted islands also occupy positions off the hollow sites. The MM is identified by giant static disorder of the Co-atoms representing the distribution of adsorption sites around the hollow site position. MD calculations are in excellent agreement with the SXRD derived results.
[1] O. Mironets, H. L. Meyerheim, C. Tusche, V.S. Stepanyuk, E. Soyka, P. Zschack, H. Hong, N. Jeutter, R. Felici, and J. Kirschner, Phys. Rev. Lett. 100, 096103 (2008)