Dresden 2003 – wissenschaftliches Programm

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SYCN: Computational nanoscience - from materials to biology

SYCN 101: Computational Nanoscience: From Materials to Biology (Hauptvortr
äge)

SYCN 101.1: Hauptvortrag

Dienstag, 25. März 2003, 14:30–15:00, ZEU/160

Modeling of tip-surface interactions in non-contact atomic force microscopy — •Ivan Stich — Center for Computational Metarials Ecience, Slovak Technical University (FEI STU), Ilkovicova 3, SK 812 19 Bratislava, Slovakia

Non-contact (NC) Atomic Force Microscopy (AFM) has developed to a very powerful experimental tool providing atomic-scale images of insulators, semiconductors, and metals alike. Despite the apparent simplicity the the complex nature of the tip-surface interaction and the mechanism of the atomic resolution in NC AFM are much less understood than the imaging mechanism of STM. The talk will focus on modeling of the short-range chemical type of tip-surface interaction which can be shown to represent a major ingredient in the atomic-scale resolution. Furthermore this interaction may lead to a considerable deformation of both tip and surface and hence affect the observed image. The imaging process will be demonstrated on a range of semiconductor (Si, InP, GaAs) and metallic (Cu) surfaces. We show that engineering of the tip apex may not only lead to spectacular modifications of the apparent AFM image but often can account for the experimentally observed AFM image. The complex nature of the tip-surface interaction makes the theoretical/computer modeling an indispensable tool for a proper understanding of the NC AFM images.