Title: Tuning Phonon Transport: From Interfaces to Nanostructures
From large-scale data centers to nano-sized transistors, thermal management plays a crucial role in device design and implementation. The effects of unoptimized thermal management, at both length scales, are clear: over half of the energy consumed by data centers is used only for cooling, and switching rates in computer processors are 300% slower today than 2005 projections. To improve these statistics, we must understand, at a fundamental level, the mechanisms which influence thermal transport, and learn to use this knowledge to modify the thermal properties with specific attention to the constraints of the intended applications.
The ability to predict, understand, and control thermal transport in materials and at interfaces remains a critical challenge and goal of nanoscale thermal transport research. In nanostructures where phonons are the primary thermal energy carriers, interfaces between dissimilar materials represent the dominant thermal resistance. An increased understanding of phonon-mediated transport across interfaces is critically needed, so that nanostructured materials can be more effectively designed and implemented.
We approached this problem experimentally, measuring nanoscale systems with time-domain thermoreflectance (TDTR), computationaly, tracking atomic thermal motion in non-equilibrium molecular dynamics simulations, and with modeling using non-equilbrium Green’s functions. This work is complicated by the wide spectra of phonon mean free paths, ranging from a single atomic spacing to the size of the material system.
My research conducted in the Nanoscale Energy Transport Laboratory at the University of Virginia, has combined both computational and experimental techniques to model, measure, and predict phonon dynamics, and the resulting thermal properties, for a wide range technologically relevant systems.
Dr. Pamela Norris is the newly appointed Vice Provost for Research at George Washington University. She previously served in roles as the Executive Dean, the Executive Associate Dean of Research, and the Associate Dean of Research and Graduate Studies in the University of Virginia School of Engineering and Applied Science and as the Frederick Tracy Morse Professor of Mechanical and Aerospace Engineering. She is a native of Portsmouth, Virginia. She joined the faculty at UVA in 1994 after receiving her undergraduate degree from Old Dominion University, her MS and PhD degrees from Georgia Tech, and completing post-doctoral studies at UC Berkeley. She is recognized globally as a leading expert in nanoscale heat transfer, especially interfacial thermal transport with a focus on thermal management across a range of length scales. She holds patents for innovative thermal management techniques for jet-blast deflectors as well as for applications of aerogels in areas ranging from biological warfare detection to lab-on-a-chip, to thermal insulation. She has served as the PI or Co-PI on over 45 sponsored research projects representing well over $25M from DOD, NSF, Industry and Foundations.
Dr. Norris is well-known for her mentoring skills and for her dedication to increasing diversity in the STEM disciplines. In 2016 she was honored with the Society of Women Engineers Distinguished Engineering Educator Award "for enduring, positive influence on students' lives as a gifted teacher, mentor, and role model; and for promoting greater diversity in STEM higher education". She is also well known for leadership in the field of nanotechnology education, chairing the American Society of Mechanical Engineers (ASME) National Nanotechnology Institute's Committee on Nanotechnology Education from 2003-2010 and organizing the first national Nano-Training Bootcamps, at the leading edge of the field. Just recently she was elected an honorary member of ASME for "international leadership in nano, micro and macroscale thermal science and engineering research; for tireless efforts to advance diversity in STEM fields; and for demonstrating engineering excellence as an outstanding mentor for students and faculty". She currently serves as the Editor-in-Chief of Nanoscale and Microscale Thermophysical Engineering, and recently served as the Vice President of Institutional Councils for the American Society for Engineering Education and as Chair of the Engineering Research Council.