Phonopy

Phonopy is an exceptional implementation of a post-process phonon analyzer that easily calculates crystal phonon properties from input information provided by external codes, such as first-principles calculation codes. This software adopts the use of a real-space method to efficiently calculate phonon frequencies with the help of force constants. These force constants are derived from atomic forces that occur when an atom undergoes a slight displacement in a supercell, which is known as the Parlinsk-Li-Kawasoe method.

Phonopy stands out from its competitors by providing automated pre- and post-processes to calculate the phonon properties. Crystal symmetry is fully included in the pre-process, which allows the user to obtain supercells having displacements from their crystal structure. This ultimate feature also permits the user to calculate atomic-forces using supercells by their preferred calculator, for instance, WIEN2k or VASP.

In the post-process, atomic forces are gathered, and the phonon properties are calculated. Additionally, a force-constants interface is included, which enables the user to calculate force-constants directly, e.g., using DFPT in VASP. Atomic-forces calculation is optional, but it is essential to create a supercell for the calculations. Phonopy can work effortlessly with any code used for calculating forces on atoms. VASP and Wien2k interfaces are built-in in this software. In conclusion, Phonopy is an exceptional software that will simplify your phonon property computations, and it is undoubtedly worth checking out.