Defects and electron-phonon coupling are frontier challenges for thermal boundary resistance theory. With Jungwan’s new Phys Rev B and papers from Jaeho and Zijian we’ve now provided new models and supporting data on both topics.
With AFOSR and DARPA support, Jungwan Cho, Zijian Li, Jaeho Lee, and Elah Bozorg Grayeli have been sorting out the contributions of near-interface defects and electron and phonon coupling to thermal boundary resistance.
Thermal boundary resistance is a long-standing problem in the heat transfer and physics communities, and one of the major remaining challenges is to understand metallic and semi-metallic systems in which both electrons and phonons contribution to conduction.
In these papers, we are using ultrafast optical characterization and patterned bridges down to 50 nm to measure volume and interface resistances in nanolayer samples. Transport analysis and experimental substraction methodologies are used to isolate the interface resistances, and then additional measurements and modeling serve to separate the electron, phonon and defect scattering contributions.