I have used a combination of VASP, Phonopy and ShengBTE to get the second order and third order force constants, born effective charges, and then thermal conductivity amongst other quantities from shengbte. I would like to plot phonon mean free path vs temperature. Any shengbte users know if this is written to an output file? Can i calculate it with the data i have?
Mean free path can be conventionally calculated from kinetic theory of gas ( Collision diameter ) . https://physics.stackexchange.com/questions/209101/whats-phonon-mean-free-path#:~:text=Phonons%20are%20quasiparticles%20that%20emerge,quanta%20of%20certain%20vibration%20modes.
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Hi Robert,
have a look e.g. at "Electrons and Phonons" , J.M.Ziman, Oxford University Press (2007) Reprint. From this you can find out which simplifications you can do and how meaningful the results will be with respect to the constrictions you made.
Dear Robert Appleton, in addition to the previous interesting answers, and the excellent classical book on Phonons by Prof. Ziman, I could recommend the following:
Reissland, J.A. (1973) The Physics of Phonons. John Wiley and Sons LTD., London.
The reason why I recommend this particular book is that it has a table where the dependence of the free path 1/l(omega) is given as a function of omega, that is the frequency, and it could be that those novel programs you use give outputs in terms of frequencies. The table is from different scattering mechanisms.
See please, Table 5.3 in section 5 on phonon-phonon interactions.
Best Regards.
Dear Robert :
As far as I know the computation of the MFP of phonons in a Lattice is a very complex calculation, since you have to compute the dispersion curves of your main modes first (anguar frecuency vs. wave number).