Woodruff School of Mechanical Engineering



Characterization of Thermal Transport in Amorphous Germanium


Freddy DeAngelis


Georgia Institute of Technology


Thursday, July 27, 2017 at 2:00:00 PM


MRDC Building, Room 3515


Courtney Aiken


While current descriptions of thermal transport exist for well-ordered materials such as crystal lattices, new methods are needed to describe thermal transport in disordered materials, including amorphous solids. Because such structures lack periodic, longrange order, a group velocity cannot be defined for thermal modes of vibration; thus, the phonon gas model cannot be applied to these structures. Instead, a new framework must be applied to analyze such materials. Using a combination of density functional theory and molecular dynamics, have analyzed thermal transport in amorphous germanium, examining how altering various material properties can affect thermal conductivity of the bulk material. We have generated dozens of new interatomic potentials using a genetic algorithm to fit to classical interatomic potentials such as Tersoff, Buckingham, and Coulomb formulations, in order to better describe germanium in an amorphous environment. We have then analyzed the effect of these various interatomic potentials on thermal conductivity, specifically with regards to how the potential alters the radial distribution function of germanium.


Freddy is a PhD candidate at the Georgia Institute of Technology. He attended Clemson University from 2009-2013, where he graduated Magna Cum Laude with a Bachelor of Science in Mechanical Energy and a minor in Mathematics. During this time, he participated in numerous research projects, including an honors research project his senior year looking at ways to improve the energy efficiency of several on-campus buildings. He enrolled at Georgia Tech in the summer of 2013, working under Asegun Henry in the Atomistic Simulation and Energy (A.S.E) research group. He earned his Master’s degree in Mechanical Engineering in 2016 working on a project investigating the use of liquid metals as a heat transfer fluid in solar thermal applications. He continues to work in the A.S.E group as a PhD candidate, with his research focusing on thermal transport in disordered materials.


Refreshments will be served.