Speakers
Invited Speaker
The functional and sometimes exotic properties of all materials – from atomically engineered designer heterostructures to human tooth enamel – can be traced back to the fundamental structures and interactions of their constituent atoms. Electron energy loss spectroscopy (EELS) in the scanning transmission electron microscope (STEM) is a powerful tool to directly probe local variations in elemental concentration as well as chemical bonding and charge distribution within precisely engineered heterostructures and across heterointerfaces. In many quantum material systems, these electronic order parameters can often be tuned or accessed only at low temperatures well below the ambient operating conditions typical for high-resolution STEM. In other materials, cryogenic sample cooling can mitigate contamination, reduce the impact of radiation damage, or stabilize vitrified soft or liquid systems. Extending EELS measurements to in situ cryogenic conditions thus opens the door to new experimental possibilities for both organic and inorganic systems. The practical realities of in situ experiments (namely, thermal drift and other mechanical instabilities associated with side-entry cooling holders), however, pose key challenges for reliable atomic-resolution cryogenic EELS measurements. In particular, the total acquisition time must be reduced without sacrificing data quality to retain atomic-scale information which is simultaneously suitable for extracting subtle chemical changes from spectral fine-structure. With new analysis approaches and ongoing instrumentation developments, including flexible in situ cryogenic sample stages, more sensitive detectors, and higher brightness electron sources, we are pushing EELS capabilities to new limits to better explore the connections between atomic-scale structure, charge, and function.
Talk Title: Cryogenic EELS at the atomic scale
Cornell University School of Applied and Engineering Physics
Bio: Berit H. Goodge is a PhD Candidate in the School of Applied and Engineering Physics at Cornell University, where she has also been recognized as a Kavli Institute at Cornell for Nanoscale Science Webb Fellow, a Microscopy and Microanalysis Student Scholar, and a Trevor R. Cuykendall Memorial Outstanding Teaching Assistant. She earned her Bachelor of Arts in physics from Carleton College. Beyond her scientific research, Berit works with the Cornell Center for Materials Research developing K-12 classroom kits to teach concepts of physics, materials, and microscopy and chairs Cornell’s Expanding Your Horizons Conference, an annual event engaging 500 middle- and high-school student attendees to encourage the discovery and pursuit of their own passions in STEM.