2021/03/02 by Mojtaba Forghani, Forghani, Mojtaba, Nicolas G. Hadjiconstantinou +1
Engineering · Materials Science · #Advanced Thermoelectric Materials and Devices #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Thermal properties of materials #Thermography and Photoacoustic Techniques
paper · pdf · doi:10.48550/arxiv.2103.01611
openalex publication_date 2021/03/02 · openalex created_date 2022/07/25 · openalex updated_date 2026/07/28
We examine the reliability of the cumulative thermal conductivity as a\nfunction of the free path, F(\Λ), in the context of reconstruction of\nphonon transport properties from thermal spectroscopy experiments. We\nspecifically show that a given F(\Λ) does not correspond to a unique\nrelaxation-times function, in the sense that more than one distribution of\nrelaxation-times can result in the same F(\Λ). Since different\nrelaxation-time distributions will, in general, lead to different thermal\nresponses, F(\Λ) does not uniquely predict the material thermal response\nin all transport regimes. This implies that in the context of thermal transport\nat the nanoscale within the Boltzmann relaxation-time approximation framework,\nthe fundamental property that should be reconstructed from the thermal\nspectroscopy experiments is the frequency-dependent relaxation-times function\n(provided group velocities are known), since it explicitly appears in the\ngoverning equation as the input material property. Extensive global\noptimization studies show that a previously proposed formulation for\nreconstruction based on the frequency-dependent relaxation-times function\n[Physical Review B 94, 155439 (2016)] provides numerically unique solutions.\n