Dresden 2009 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 40: Methods: Scanning probe techniques I

O 40.3: Vortrag

Mittwoch, 25. März 2009, 15:30–15:45, SCH A316

High Resolution 3D-Force-Field-Spectroscopy on Fe/W(001) — •Rene Schmidt, Cesar Lazo, Uwe Kaiser, Alexander Schwarz, Stefan Heinze, and Roland Wiesendanger — Institut für Angewandte Physik, Universität Hamburg

Three-dimensional force fields with atomic resolution have been measured by atomic force microscopy in the non-contact regime (NC-AFM) in ultrahigh vacuum and at low temperatures. Force spectroscopy allows a site specific determination of the distance dependence of tip and sample interaction potential and force on the investigated system. Here, we study a purely metallic system, i.e., the iron monolayer epitaxially grown on a W(001) substrate with a metallic tip.

The high resolution data consists of 128×128 curves on a 2 nm×2 nm surface area. The curves were recorded in a distance range of 270 pm close to the surface with Δ z-steps of 10 pm. Additionally, one single curve was recorded up to a distance of 20 nm to determine the long-range tip-sample forces. The resulting total force at each lattice site can be separated into long- and short-range contributions. The experimentally obtained short-range forces are compared quantitatively with first principles calculations based on density functional theory.