Heat Under the Microscope:
 Uncovering the Microscopic Processes that Govern 
Thermal Transport

By Austin Minnich

Mechanical Engineering, California Institute of Technology, Pasadena, CA

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Thermal transport is a ubiquitous process that incorporates a wide range of physics and plays an essential role in nearly every technological application, ranging from space power generation to consumer electronics. In many solids, heat is carried by phonons, or quanta of lattice vibrations. Compared to other energy carriers such as electrons or photons, the microscopic transport properties of thermal phonons remain remarkably poorly understood, with much of our understanding still based on semi-empirical studies from over fifty years ago. In this talk, I will describe our efforts to uncover the microscopic processes that govern thermal transport by phonons. In particular, I will describe how our advances in computation and experiment have enabled the first direct measurements of thermal phonon transmission coefficients at solid interfaces. I will demonstrate how these insights are advancing applications ranging from thermoelectric waste heat recovery to radio astronomy.


Austin Minnich Austin Minnich is an Assistant Professor of Mechanical Engineering and Applied Physics at Caltech. He received his Bachelor's degree in Engineering Science from UC Berkeley in 2006, followed by an S.M. and Ph.D from MIT's Mechanical Engineering in 2008 and 2011, respectively. He started his faculty appointment in September 2011. He is the recipient of a 2013 NSF CAREER award and 2015 ONR Young Investigator Award.

Professor Minnich researches the physics and engineering of nanoscale heat transport. Nanostructured materials have novel thermal properties with applications in energy such as for thermoelectric materials, which convert heat directly to electricity. Minnich uses experimental techniques, including ultrafast optical experiments, to study transport at the length and time scales of the energy carriers themselves. These experiments measure properties of the energy carriers that are lost at macroscopic scales, allowing for a more complete understanding of nanoscale transport physics. Minnich also uses these results to design novel materials and thermal devices, such as more efficient thermoelectric materials and devices for thermal energy storage.

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Cite this work

Researchers should cite this work as follows:

  • Austin Minnich (2016), "Heat Under the Microscope:
 Uncovering the Microscopic Processes that Govern 
Thermal Transport," http://nanohub.org/resources/24649.

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