A quantum field theory of phonons in crystals extended to the multi-band model II

The three-band model is applied to fcc structure crystals. The dynamical matrix is calculated by using fundamental coupling constants like chemical bondings. As the temperature decreases, the theory reduces that in the two-band model. There are three Nambu-Goldstone bosons which originate from those in the two-band model. Higher excited states modify the phonon dispersion curves derived in the two-band model. The three-band model clarifies the physical background of the shell model.