Electronic and geometric structure of nano-materials: synchrotron radiation studies

Abstract

Designing a surface with predefined characteristics to work as a catalyst for a specific reaction, or to have specific magnetic properties, or to have a stable interface with an underling support (as is needed for high k materials on a silicon wafer to produce nano CMOS semiconductor device) has been the long-term goal of many surface scientists. So far it has been a elusive goal, but one can be absolutely convinced that any progress in this direction will be based on a complete understanding of the inter play between electronic structure and the position of the atoms on the surface or at an interface. These atoms find themselves in an environment that has few symmetries, nearest neighbors can be different from site to site, atomic distances likewise. Over all it is the electronic structure of the atoms that defines these features, but sometimes the atomic arrangement can influence the electronic structure. The study of this kind of inter-relation requires the use of different experimental techniques and computational approaches. In Brazil very few centers have groups that have these kinds of capabilities. In this thematic project we will try to update the experimental infrastructure operated by the Surface Group in 'Campinas' (UNICAMP/LNLS/UFSCAR) and use the research and 'training' associated with a DFG/IRTG project with Uni Dortmund to help develop our experimental and theoretical capabilities. We will explore these interactions basically in the types of structure, surface alloys, metal oxide nanoparticle systems and semiconductor oxide interfaces, using XPS, PED and STM. Systems with catalytic properties, magnetic properties or electronic properties will be studied. (AU)