March 5
@
4:00 PM
–
5:00 PM
The ME 903: Graduate Student Lecture Series features campus and visiting speakers who present on a variety of research topics in the field of mechanical engineering. Professor Dakotah Thompson is an assistant professor at the University of Wisconsin – Madison.
Presentation Title: Misbehaving metals: from anomalous radiative transport to non-Drude behavior.
Abstract: Classical theories governing radiative heat transfer are based on geometrical optics, which presumes that light is a ray. While useful for most engineering applications, this conception is not completely general because it does not account for wave effects like optical interference and diffraction. In this talk, I discuss a limiting case where the size of the objects exchanging heat is much smaller than the radiation wavelengths. Recent work from my group highlights the limitations of Planck’s blackbody law, and reveals that radiative transport between nanoscale objects comprised of polar dielectrics and metals may exhibit qualitatively different size scaling. Overall, these transport characteristics are largely determined by electromagnetic surface modes which are highly dependent on the material’s optical properties. In the second part of the talk, I discuss how optical properties and their frequency dispersion are modeled. Specifically, I will introduce an extended Drude model that can ensure Kramers-Kronig consistency and can accurately predict the optical properties of disordered conductors in the far infrared. Examples of such materials include liquid metals, ionic liquids, cuprate superconductors, and transparent conducting oxides. Overall, the results underlying these studies were obtained using advanced calorimetric and ellipsometric techniques, so experimentalists are highly encouraged to attend.
Bio: Dakotah Thompson has been a faculty member in the Mechanical Engineering department at UW-Madison since 2019. Dakotah earned his Ph.D. at the University of Michigan in 2018, and his B.S. at Georgia Tech in 2012. Dakotah’s core technical expertise is in nanofabrication and heat flow calorimetry, and he has published several high-impact works in the field of radiative thermal transport.