shera-amit / phonons

Contains phonon calculations scripts using phonopy and vasp

Phonon Calculations with Phonopy and VASP

This repository provides a set of Python and shell scripts for performing phonon calculations using Phonopy and VASP. The workflow consists of the following steps:

1. Prepare the necessary input files for VASP.
2. Run VASP calculations on displaced structures.
3. Collect forces and generate the FORCE_SETS file.
4. Calculate the force constants and the phonon band structure.
5. Plot the phonon band structure.

Prerequisites

• VASP (properly installed and configured on your system)
• Phonopy
• NumPy
• Matplotlib

Install the required Python packages using pip:

pip install phonopy numpy matplotlib

Usage

1. Place your VASP POSCAR file in the working directory.

2. Modify the prepare_phonon_calculation.py script to set the supercell size for the phonon calculation. Then, run the script to generate displaced structures and the disp.yaml file:

python prepare_phonon_calculation.py

3. Prepare the necessary VASP input files (INCAR, KPOINTS, POTCAR) for running the calculations on the displaced structures.

4. Update the num_displacements variable in the run_vasp_phonon.py script according to the number of displacement configurations. Adjust the VASP command and the number of processors as needed. Run the script to perform VASP calculations on the displaced structures:

python run_vasp_phonon.py

5. Run the collect_forces.py script to collect forces from the VASP calculations and generate the FORCE_SETS file:

python collect_forces.py

6. Create a Phonopy configuration file (phonopy.conf) to define the settings for the band structure calculation. Adjust the supercell size (DIM), mesh size (MP), and band paths (BAND) as needed:

7. Run Phonopy to calculate the force constants and the phonon band structure:

phonopy -c POSCAR --fc FORCE_SETS --dim="2 2 2" --band="0 0 0 0.5 0.5 0 0.5 0.5 0.5 0 0 0"

8. Run the plot_band_structure.py script to visualize the phonon band structure: