Introduction: A new approach for expressing the lattice thermal conductivity of diatomic
nanoscale materials is developed.
Methods: The lattice thermal conductivity of two samples of GaAs nanobeam at 4-100K is calculated
on the basis of monatomic dispersion relation. Phonons are scattered by nanobeam boundaries,
point defects and other phonons via normal and Umklapp processes.
Results: A comparative study of the results of the present analysis and those obtained using
Callaway formula is performed. We clearly demonstrate the importance of the utilised scattering
mechanisms in lattice thermal conductivity by addressing the separate role of the phonon scattering
relaxation rate. The formulas derived from the correction term are also presented, and their difference
from Callaway model is evident. Furthermore their percentage contribution is sufficiently
small to be neglected in calculating lattice thermal conductivity.
Conclusion: Our model is successfully used to correlate the predicted lattice thermal conductivity
with that of the experimental observation.