Research

Recent developments in instrumentation have made it a very exciting time to perform both fundamental and applied research in the electron microscope. Aberration correctors have taken spatial resolution below the 1 angstrom barrier for inorganic materials and promise to do the same for organic/biological materials. In-situ microscopy is moving forward at a rapid pace with the development of gas/liquid stages that permit reaction processes to be imaged and analyzed at atomic resolution. The development of nanosecond and faster photoemission electron sources offers the chance to move the high spatial resolution world of electron microscopy into the ultrafast world of materials dynamics.

Conventional in-situ TEM coupled with ultrafast TEM can be utilized to gain a fundamental understanding of dynamic processes occurring in materials and biological structures. The combination of these capabilities allow for vast improvements of in-situ TEM studies limited by video rate in that many processes span multiple time and length scales. Ultrafast dynamic in-situ electron microscopy promises to answer the challenging questions in the fields ranging from materials science to biology.

The promise of ultrafast and in-situ TEM is to elucidate the changes in the configuration of materials along dynamical pathways in situ while they are occurring. Dynamic material behaviors that would benefit from study with high spatial and temporal resolution include phase transformations, solid-state chemical reactions, melting and solidification and shock propagation, etc. Such observations will allow the direct measurement of constitutive quantities needed in models and the dynamic validation of many types of materials simulations at different length scales.

In Ortalan group, to reveal the fundamental properties and the dynamics of the structural and chemical transformations in materials, we utilize the-state-of-the-art Ultrafast TEM (UTEM), Aberration-Corrected and In-situ Transmission Electron Microscopy, Nanoscale Electron Tomography, Electron Energy Loss Spectroscopy (EELS) and Density Functional Theory (DFT). You will find brief descriptions of some of these efforts in our group below.