ABSTRACT
However, for discussing the essential features of the temperature variation of the lattice thermal conductivity results, it is often sufficient to use a simplified relation, the Debye formula [52]:
= iCLvs lp (27) where CL is the lattice heat capacity at constant volume, vs the velocity of sound, and lp a phonon mean free path. The Debye formula is based on the dominant phonon mode approximation, which avoids the complexity of considering the entire phonon spectrum, with a velocity and mean free path associated with each phonon mode and polarization.
