Phase Transformations of Nanoscale Systems Using TEM, Professor Judy Cha of Yale University
Thursday, September 24, 2020 at 4:00pm to 5:00pmVirtual Event
The Materials Science and Engineering Seminar Series presents Professor Judy Cha of Yale. Professor Cha will present her talk "Phase Transformations of Nanoscale Systems Using TEM"
Many nanoscale systems undergo phase transformations in response to stimuli, which subsequently change the properties of the systems, thereby providing opportunities to create smart devices. Here, Professor Cha’s lab employs in situ transmission electron microscopy (TEM) to study how phase transformations occur and deviate and how they are controlled at the nanoscale under electrical biasing, heating, and cooling; and to examine their effect on materials properties. Professor Cha will discuss three examples of phase transformation: IBM’s confined phase change memory (PCM) cells with a surfactant layer, which showed a record endurance of 2x1012 programming cycles; metallic glass nanostructures that are crystallized to test the limits of classical nucleation theories; and the ferroelectric transition of topological crystalline insulator SnTe nanowires, which has implications for the recently observed novel superconductivity. In all three examples, in situ TEM investigations reveal detailed and unexpected phenomena and rich structural and chemical heterogeneities, guiding researchers to build better models and theories for nanoscale phase transformations. Professor Cha also hopes to discuss her lab’s recent results on the phase transformations of two-dimensional transition metal dichalcogenides induced by electrochemical intercalation of Li+ and their energy applications.