Role of Longitudinal and Transverse Phonons in Lattice Thermal Conductivity of GaAs and InSb

The lattice thermal conductivity of GaAs and InSb has been calculated in the temperature range 2-300^∘{}K taking into consideration the details of phonon dispersion relations resulting in the separate contributions of the longitudinal and transverse phonons. This analysis gives a much better fit to the experimental data throughout the whole range of temperature than is given by Callaway's formulation which is based on Debye's phonon spectrum, a choice of relaxation time for phonon-phonon scattering relaxation time which is valid for longitudinal phonons, and the use of the average phonon velocity.