February 13
@
1:00 PM
–
2:00 PM
UW-Madison Department of Materials Science and Engineering welcomes Assistant Professor Samuel Teitelbaum. Their seminar on “Uncovering Real-time Structural Transformations with Femtosecond X-rays” will be on Thursday, Feb. 13 in MS&E 265 from 1 p.m. to 2 p.m.
Abstract
Material transformations (i.e. phase transitions) are foundational processes in technologies and natural phenomena from solid-state memory and piezoelectric motors to the composition of mountains. Despite their broad importance, experimentally observing the underlying atomic-scale dynamics in these transformations remains an open challenge. Addressing this challenge requires tracking phenomena over a broad range of time and length scales, ranging from the timescale of atomic vibrations (10-13 seconds) to domain percolation (103 seconds or longer), and length scales from atomic bonds (10-10 meters) to domain sizes (10-3 meters). Over the past decade, ultrashort x-ray sources such as x-ray free electron lasers (XFELs) enabled unique experimental methods that can probe this broad range of length and time scales. In this talk, I will show how XFELs can reveal key details about the multiscale dynamics of phase transitions. Using charge density waves (CDW) systems as a prototypical example, we show how ultrafast x-ray scattering reveals even ultrashort phase transitions to be intrinsically heterogeneous, and the role that topological defects play in coarsening dynamics on very short timescales.
Though XFELs offer a powerful probe into material dynamics, XFELs cost billions of dollars and can only run a limited number of experiments simultaneously. This creates a bottleneck for fully realizing the potential of these sources. In the second part of my talk, I will discuss our efforts to build more compact, lower-cost ultrafast x-ray sources. I will discuss the design and early commissioning results of two sources, the compact x-ray source (CXLS) and the compact XFEL (CXFEL). These sources have physical footprints and capital cost orders of magnitude smaller than a typical XFEL, fitting within a typical university building. Finally, I will give an outlook on these compact sources’ applications in condensed matter physics, AMO science, and biochemistry.
Bio
Samuel Teitelbaum grew up in the suburbs of Washington, DC, and obtained a BS in chemistry and physics at the University of Maryland, College Park. He attended MIT for graduate school, working on single-shot spectroscopy of light-driven phase transitions, and obtained a PhD in Physical Chemistry in 2016. His postdoctoral work at SLAC focused on using XFELs to understand optically driven states, including nonlinear x-ray optics, coherent x-ray scattering, and time-resolved x-ray scattering. He joined the faculty at Arizona State University as an assistant professor in 2020.