Dernov, Andrei2024-03-292024-03-292023-03https://hdl.handle.net/11299/261972University of Minnesota M.S.M.E. thesis. March 2023. Major: Mechanical Engineering. Advisor: Traian Dumitrica. 1 computer file (PDF);vi, 47 pages.With device dimensions shrinking toward nanoscale sizes, an accurate understanding and modeling of the energy transfer mechanisms at metal-nonmetal interfaces is highly desirable. To model the thermal transport across Au-GaN interface, we developed a general multitemperature model (MTM) that accounts for both electron and phonon transport and allows for a nonequilibrium phonon population described as a sum of thermal distributions of the phonon branches. The model ispopulated with material parameters calculated from ab initio calculations and used to describe the temperature profile across Au-GaN junction 400 nm in length subjected to constant temperature differential, continuous wave laser heating of Au, and constant heat flux on GaN. The calculated steady-state and time dependent temperature profiles reveal strongly nonequilibrium electron-phonon and phonon-phonon interfacial regions created through energy carrier coupling. Our results indicate that multitemperature based model is required for resolving the thermal energy flow across metal-nonmetal interfaces. Our MTM advances the theoretically tool to investigate nonequilibrium thermal transport across metal-nonmetal interfaces and provide a perspective of designing and controlling the thermal transport in electronic devices.enThesis or Dissertation