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MM: Fachverband Metall- und Materialphysik

MM 9: Topical Session TEM III

MM 9.1: Topical Talk

Monday, March 14, 2011, 15:45–16:15, IFW A

Advanced electron microscopy and first-principles calculations: New insights into materials science on the atomic scale — •Rolf Erni — Electron Microscopy Center, Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland

New electron optical devices, such as monochromators, spherical and chromatic aberration correctors, have boosted the resolution in (scanning) transmission electron microscopy. In parallel, the revolutionized optics has increased the sensitivity of the imaging techniques to a level where, for instance, the dynamics of individual atoms can be monitored, employing a microscope setting tailored to the material to minimize radiation damage. This overall progress has opened the possibility to reliably study smaller materials systems; while typically in conventional microscopy millions of atoms constitute a high-resolution micrograph, the new optics allows for monitoring systems that are merely defined by a few hundred atoms, which indeed is a requirement if the functionality of a nano-device needs to be analyzed. As a consequence, nowadays microscopy data can provide direct input for first-principles calculations. Indeed, combining the theoretical and the experimental approach leads to synergies that simplify finding answers for new observations. The advantage of this tandem approach is demonstrated by discussing the dynamics and stability of ad-atoms and ad-molecules on suspended graphene. Moreover, while most atomic-scales studies are confined to two-dimensional projections, an outlook is given on how the third spatial dimension could be explored.