2017/09/06 by Ahmed Hamed, Hamed, Ahmed, Anter El–Azab +1
Engineering · Materials Science · #FOS: Physical sciences #Machine Learning in Materials Science #Materials Science (cond-mat.mtrl-sci) #Thermal properties of materials #Thermography and Photoacoustic Techniques
paper · pdf · doi:10.48550/arxiv.1709.01876
openalex publication_date 2017/09/06 · openalex created_date 2022/10/03 · openalex updated_date 2026/07/28
The inelastic nature of 3-phonon processes is investigated within the\nframework of perturbation theory and linearized Boltzmann Transport Equation.\nBy considering the energy conservation rule governing this type of interactions\nin a statistical average sense, the impact of different forms of the\nregularized energy-conserving Dirac delta function on 3-phonon scattering rates\nwas evaluated. Strikingly, adopting Lorentz distribution, in accordance with\nthe shape of eigenenergy broadening of phonon normal modes due to the leading\nterm of crystal anharmonicity, was found to play a critical role in activating\numklapp processes at low temperature, leading to intrinsic lattice thermal\nconductivity peak at finite temperature for perfect crystal. This\ncharacteristic behavior, unique to the Lorentzian, lays foundation for\ndeveloping adjustable-parameter-free computational models for reliable\nprediction of the finite lattice conductivity at low temperature, even in the\nabsence of extrinsic scattering processes. An iterative solution scheme for\nBoltzmann Transport Equation was used to compute the intrinsic thermal\nconductivity of solid argon over the entire temperature range (2-80 K). For the\nfirst time, the experimentally observed T2 behavior in the low temperature,\nT, limit and the peak temperature (~ 8 K) were successfully recovered, in\naddition to the classical high temperature T-1 behavior above 20 K by the\nsole use of 3-phonon processes. The good agreement with experiment indicates\nthat phonon-phonon interactions dominate over the entire temperature range in\nargon, contrary to previous hypotheses that phonon-defect scattering dominates\nthe sub-peak regime. Anisotropy in thermal conductivity of single crystal at\nlow temperature due to phonon focusing was observed. In addition, argon\nconductivity is underestimated by an order of magnitude in Single Mode\nRelaxation Time approximation.\n