Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 36: Poster Session II (Metals; Nanostructures at surfaces; Surface or interface magnetism; Spin-Orbit Interaction at Surfaces; Electron and spin dynamics; Surface dynamics; Methods; Theory and computation of electronic structure)
O 36.45: Poster
Dienstag, 15. März 2011, 18:30–22:00, P4
Laterally resolved dependence of the surface-state band edge on Ag islands on Nb (110) — •Tihomir Tomanic1, Christoph Sürgers1, Dominik Stöffler1, and Hilbert v. Löhneysen1,2 — 1Karlsruher Institut für Technologie, Physikalisches Institut, 76131 Karlsruhe — 2Karlsruher Institut für Technologie, Institut für Festkörperphysik, 76021 Karlsruhe
We investigate the growth of Ag on Nb (110) by in-situ STM at low temperatures (Tmin = 3 K). The surface of a Nb (110)-oriented single crystal is prepared by repeated cycles of flashing up to 2300 ∘C and subsequent Ar+ sputtering. At a substrate temperature TS = 573 K, evaporation of nominal 5 nm Ag on Nb (110) leads to the formation of large, flat, and well separated islands. On top of these islands the band edge of electronic surface state in the Γ-L bandgap is resolved by local tunnelling spectroscopy. This state is shifted by 70 - 100 meV towards the unoccupied band - when compared to homoepitaxially grown Ag on Ag (111) - due to large tensile strains originating from the difference in thermal expansion of Ag and Nb between 573 and 3 K. This allows a laterally resolved investigation of the strain distribution in these Ag islands on the nanometer scale.
Work supported by the Kompetenznetz Funktionale Nanostrukturen der Baden-Württemberg Stiftung and by the DFG Center for Functional Nanostructures.