Dresden 2009 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 25: Surfaces and films: forces, structure and manipulation
O 25.5: Vortrag
Dienstag, 24. März 2009, 16:00–16:15, SCH A118
Surface reconstruction of clean bcc-Fe{110}: a quasi-hexagonal top-layer with periodic height modulation — •Toyo Kazu Yamada1,2, Hidetoshi Tamura2, Motoyuki Shishido2, Toshikazu Irisawa2, Lukas Gerhard1, Wulf Wulfhekel1, and Tadashi Mizoguchi2 — 1Physikalisches Institut, Universität Karlsruhe, Wolfgang-Gaede-Straße 1, 76131 Karlsruhe, Germany — 2Faculty of Science, Gakushuin University, 1-5-1 Mejiro, Toshima 171-8588, Tokyo, Japan
In general every surface has stress due to a symmetry break. When the stress overcomes the elastic limit, the surface reconstructs. There have been found surface reconstructions on only several metal surfaces. So far, no surface reconstruction was reported on the Fe surface. Iron is an important popular ferromagnetic metal which has been widely used since the ancient age in practical applications owing to its strength and abundance. We use Fe single crystals made by a chemical vapor deposition technique, which include no impurities in bulk and give us an extremely clean surface.
We found a new surface reconstruction on the {110} plane of bcc Fe-whisker single crystals. Atomically-resolved STM images showed a quasi-hexagonal atomic array with mesoscopic-range periodic height modulation of about 1/3 of an atomic step. This height modulation was found to be a result of an interference between the quasi-hexagonal top-layer and the sub-surface bcc-Fe{110} layer. Details of the atomic structure as well as local density of states of this new reconstruction are presented.