The primary thrust of our research is to explore how electronic and structural changes on small length scales affect the macroscopic properties of materials. In particular: how interfaces affect transport properties (eg. in 5-atom thick gate oxides we have used atomic-scale electron energy loss spectroscopy to place fundamental physical limits on device scaling - Nature paper and viewpoint); the role of electronic structure in controlling the cohesion of interfaces (Phys. Rev. Lett.); and the first detection and real-space characterization of individual dopant atoms and clusters buried inside crystals. In many cases, our tool of choice will be an atomic-resolution electron microscope.

We are always looking to develop new methods that advance electron microscopy, including developing new detectors that allow us to explore new physics, and using novel sample holders and microscopes to image vacuum sensitive materials.

Areas of interest:

• Physics of renewable energy including the nanostructure of Fuel Cells, Batteries, and Photocatalysts and their real-time evolution during operation.
• Structure and properties of two-dimensional materials.
• Atomic-scale perovskite heterostructures: atom-by-atom design of materials that do not exist in nature, explored for extreme dielectric and nonlinear properties.
• Physical limits placed by interfacial electronic structure and atomic-scale chemistry on the scaling of integrated circuits.
• Development of high-resolution, low-dose methods for electron imaging and tomography of beam sensitive nanostructures.
• Mapping photonic and plasmonic structures with nm-sized relativistic electron beams
• Development of new electron microscopy methods and instrumentation

 Selected Research Projects

Three-dimensional imaging of nanostructures using electron tomography.

Characterization of Carbon Corrosion-Induced Structural Damage of
PEM Fuel Cell Cathode Electrodes Caused by Local Fuel Starvation

Work in collaboration with General Motors through the Cornell Fuel Cell Institute.

"Atomic-Scale Chemical Imaging of Composition and Bonding by Aberration-Corrected Microscopy",
D. A. Muller, L. Fitting Kourkoutis, M. Murfitt, J. H. Song, H. Y. Hwang, J. Silcox, N. Dellby,
O. L. Krivanek, Science319, p. 1073 (2008)"

Cornell Chronicle: A STEM in Color

Science Daily: New Electron Microscope Identifies Individual Color-coded Atoms