Udo D. Schwarz (Yale University)
October 21
2:00 p.m
ABSTRACT:
An ability to shape the nanoworld is of great scientific and technological interest. In this talk, we show two unusual approaches that both allow the formation of structures down to atomic precision. First, we are capitalizing on the fact that with the continued development of scanning probe microscopy techniques, manipulation of single molecules has become possible, providing unprecedented insight into chemical reactions at the single-molecule level. Here, we conducted controlled manipulation experiments with benzene on a Cu (100) surface as a model system. The results indicate that the molecules were either pushed, pulled, dragged, jumped to the tip, or did not move depending on the chemical surroundings of the molecules and the chemical identity of the tip. Comparison with computational results suggests that the presence of the tip lowers the energy barrier the molecule has to overcome during its motion, which evolves with the chemical identity of the tip. Our results nevertheless indicate that a reliable methodology where surface reactions can be induced by the tip of a scanning probe microscope and the reaction pathway is chosen at will could be in reach, which would ultimately enable an individualized, site-specific understanding of single-molecule surface chemistry.
In the second part of the talk, we will then expand on the theme of atomic-scale shaping by asking how surface morphologies of samples as large as multiple mm2 can be created at will with Angstrom precision. Here we demonstrate the atomically precise imprinting of atomic step structures of a SrTiO3 single crystal used as mold into a Pt-based bulk metallic glass (BMG).
BIOGRAPHY:
Udo D. Schwarz graduated in 1989 from the University of Basel, Switzerland, receiving his Ph.D. in physics from the same institution in 1993. Subsequently, he continued his work as a staff scientist and lecturer at the Institute of Applied Physics of the University of Hamburg, Germany. In 2001, Prof. Schwarz moved to the Materials Science Department of the Lawrence Berkeley National Laboratory in Berkeley, California. Since 2002, he works at Yale’s Mechanical Engineering Department, where he got promoted to full professor in 2009 and serves as department chair since 2012. His research interests concern the local measurement of atomic-scale interactions and properties by applying scanning probe microscopy techniques and other local probe techniques such as nanoindentation to study problems in surface physics, catalysis, friction, elastic deformation, and plastic flow, as well as the study of local mechanical, chemical and electronic properties of novel materials such as metallic glasses or two-dimensional materials. In addition, Prof. Schwarz is also interested in nanoimprint techniques and the nanostructuring of surfaces as well as the high-throughput discovery of novel materials.
The talk recording is available here.