MSE Seminar - Professor Udo Schwarz, Yale University
Dr. Udo D. Schwarz
Professor and Chair
Departments of Mechanical Engineering & Materials Science and Chemical & Environmental Engineering and Center for Research on Interface Structures and Phenomena (CRISP)
Yale University, New Haven, CT 06520, USA
Extending the Capabilities of Scanning Probe Microscopy:
Multidimensional Atomic Resolution Imaging with Chemical Selectivity
Monday, August 24, 2015
4:00 p.m. MARC (GTMI/Callaway Bldg.) Auditorium
Reception at 3:30 p.m. in the MARC Atrium
Despite the evolution of scanning probe microscopy (SPM) into a powerful set of techniques that image surfaces and map their properties down to the atomic level, significant limitations in both imaging and mapping persist. Currently, typical SPM capabilities qualitatively record only one property at a time and at a fixed distance from the surface. Furthermore, the probing tip’s apex is chemically and electronically undefined, complicating data interpretation. To overcome these limitations, we have started to integrate significant extensions to existing SPM approaches. First, we extended noncontact atomic force microscopy with atomic resolution to three dimensions by adding the capability to quantify the tip-sample force fields near a surface with picometer and piconewton resolution [1,2]. Next, we gained electronic information by recording the tunneling current simultaneously with the force interaction . In this talk, we will specifically focus on illustrating how the tip chemistry, tip asymmetry, and the tip-sample distance influence the recorded interactions – and thus the information you can gain from images. Through a combination of experimental work and theoretical analysis, we first show with the example an oxygen/copper(100) surface phase how specific atomic species can be selectively imaged in both the force and the current channels depending on the choice of imaging parameters and tip chemistry [3, 4]. From this platform, we present our vision of a method capable of characterizing full atomic-scale chemical and electronic properties with further examples that include strontium titanate, titanium dioxide, and graphite.
 B. J. Albers et al., Nature Nanotechnology 4, 307 (2009).
 M. Z. Baykara et al., Advanced Materials 22, 2838 (2010).
 M. Z. Baykara et al., Physical Review B 87, 155414 (2013).
 H. Mönig et al., ACS Nano 7, 10233 (2013).
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, including electric, magnetic, chemical, and nanotribological interactions, using scanning probe microscopy techniques to study problems in surface physics, catalysis, friction, and adhesion.