Si phonon dispersions

CRYSTAL output file is crystal.o. This is the default file name
for the CRYSTAL interface, so, the -c crystal.o parameter is not needed

1) Create displaced supercells:
   phonopy --crystal --dim="4 4 4" -d
   Complete CRYSTAL inputs can be prepared manually
   or with the help of a template (see TEMPLATE)

2) Run the supercell input with CRYSTAL
   Here supercell-001.o has been pre-calculated with CRYSTAL17.

3) Collect forces:
   phonopy --crystal -f supercell-*o

4) Calculate phonon dispersion data into band.yaml and save band.pdf:
   phonopy --crystal --dim="4 4 4" -p -s band.conf

   Plot the phonon dispersion in cm^{-1} units:
   (factor = CrystalToTHz * THzToCm = 15.633302 * 33.356410)
   phonopy --crystal --dim="4 4 4" -p -s --factor=521.47083 band.conf

   Create a formatted plot (here band.yaml is in cm^{-1) units):
   phonopy-bandplot --fmin=0 --line --ylabel="Frequency (cm\$^{-1}\$)" --band-labels="`grep BAND_LABELS band.conf | cut -d= -f2-`" -o dispersion.pdf

