First-principles Phonon Calculations with Phonopy and Phono3py

Harmonic, quasi-harmonic, and anharmonic phonon properties of crystals are getting to be better predicted using first-principles phonon calculations by virtue of the progress of the calculation methods and increasing computer power. In this review, basic formulae of phonon properties are reviewed with the phonon calculation examples performed using the phonon calculation codes, phonopy and phono3py, combined with the first-principles calculations. The computational workflow to utilize the first-principles phonon calculation is straightforward and its automation is of great interest to science. Therefore, a few practical applications of the automated first-principles phonon calculations are also presented.