Berlin 2008 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 12: Symposium: Size-Selected Clusters at Surfaces I
(Invited Speakers: Karl-Heinz Meiwes-Broer, Heinz Hövel, Thorsten Bernhardt)
O 12.7: Vortrag
Montag, 25. Februar 2008, 16:00–16:15, MA 005
Size-dependent Surface States on Strained Cobalt Nanoislands on Cu(111) — •Benjamin Heinrich1, Mircea-Vasile Rastei1, Laurent Limot1, Pavel A. Ignatiev2, Valeri S. Stepanyuk2, Patrick Bruno2, and Jean-Pierre Bucher1 — 1Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, Université Louis Pasteur, F-67034 Strasbourg, France — 2Max-Planck-Institut für Mikrostrukturphysik, D-06120 Halle/Saale, Germany
Nanoislands on metal surfaces have been a matter of intense research for decades in view of prospective applications in a vast variety of domains. One of the main challenges in this regard is to control the interplay between the physical properties, whether magnetic, electronic or chemical, and the lattice mismatch with the metal substrate, which results in changes due to strain.
In this work, we focus on the interplay between strain relaxations and the surface states of Co nanoislands on Cu(111). By low-temperature scanning tunneling spectroscopy (LT STS), taken over the islands, we show for the first time that the electronic states of the islands vary with their size: Occupied surface states exhibit a sizeable downward energy shift as the island size decreases. Atomic-scale simulations and ab initio calculations confirm that the driving force for the observed shift is related to size-dependent mesoscopic relaxations in the nanoislands.