Regensburg 2004 – wissenschaftliches Programm

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O: Oberflächenphysik

O 23: Rastersondentechniken II

O 23.2: Vortrag

Dienstag, 9. März 2004, 16:00–16:15, H36

Energy dissipation in non-contact AFM — •Domenique Weiner, Andre Schirmeisen, and Harald Fuchs — Physikalisches Institut and CeNTech, University of Muenster, Wilhelm-Klemm-Str. 10, 48149 Muenster, Germany

The atomic force microscope (AFM) driven in the non-contact mode offers the possibility to measure long-range and short-range forces. Furthermore, energy dissipation mechanisms can be studied which are up to now not well-understood and are subject of current research [1]. One important step towards a better understanding of the energy dissipation is to study the temperature dependence of the effect [2].

We measure the damping signal on a Au (111) surface which is prepared under ultra-high vacuum (UHV) conditions by sputtering and annealing. The commercial silicon cantilevers are covered with a PtIr-layer of about 30 nm thickness to ensure the measurement of a true metal contact. We use an UHV-VT-AFM (Omicron) which is integrated in a two chamber-apparatus. We investigate the frequency shift and the damping simultaneously as a function of tip-sample separation for different sample temperatures. Therefore we are able to gain quantitative values of the dissipation which are compared to current dissipation models like van der Waals friction [1], electrical dissipation [3] or dissipation induced by inhomogeneous tip-sample electric fields [2].

[1] Volokitin, Persson, Phys. Rev. Lett. 91, 06101, 2003

[2] B. C. Stipe, H. J. Mamin, T. D. Stowe, T. W. Kenny, D. Rugar,

Phys. Rev. Lett. 87, 096801, 2001.

[3] W. Denk, D. W. Pohl, Appl. Phys. Lett., Vol. 59, No. 17, 1991