2015/04/18 by Ashok T. Ramu, John E. Bowers, Ramu, Ashok T. +1
Chemistry · Engineering · Materials Science · Physics and Astronomy · #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Thermal Radiation and Cooling Technologies #Thermal properties of materials #Thermography and Photoacoustic Techniques #cond-mat.mes-hall #thermodynamics and calorimetric analyses
paper · pdf · doi:10.48550/arxiv.1504.04775
openalex publication_date 2015/04/18 · arxiv created 2015/08/20 · arxiv updated 2015/08/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A recently developed enhanced Fourier law is applied to the problem of extracting thermal properties of materials from frequency-domain thermoreflectance (FDTR) experiments. The heat transfer model comprises contributions from two phonon channels; one a high-heat-capacity diffuse channel consisting of phonons of mean free path (MFP) less than a threshold value, and the other a low-heat-capacity channel consisting of phonons with MFP higher than this value that travel quasi-ballistically over length scales of interest. The diffuse channel is treated using the Fourier law, while the quasi-ballistic channel is analyzed using a second-order spherical harmonic expansion of the phonon distribution function. A recent analysis of FDTR experimental data suggested the use of FDTR in deriving large portions of the MFP accumulation function; however, it is shown here that the data can adequately be explained using our minimum-parameter model, thus highlighting an important limitation of FDTR experiments in exploring the accumulation function of bulk matter.