How do I extract the wave function from a VASP calculation?

Question

We can obtain a energy band structure of a crystal from a DFT calculation in Vasp. Each point in each band represents an energy eigenvalue with a corresponding wave function from the Schrödinger equation. I want to choose a specific K-point in the Brillouin zone for a specific band and investigate the symmetry of the corresponding wave function.

Supposedly, I can obtain the wave function from the WAVECAR file. It should yield a number of coefficients which can be used to construct the wave function from the basis functions used in the calculations. However, I do not need the full wave function. I only want to know the symmetry of the function. If my basis was small, I could easily identify the symmetry by inspection, but with hundreds (?) of coefficients this seems difficult.

How can I find the symmetry of the wave function from my VASP calculation? Please, also let me know if it seems like I am asking the wrong question.

Answer 1

It seems you are looking for a package to compute the irreducible representation of electronic states computed by VASP. This has been recently developed:

J. Gao J, Wu Q, Persson C, Z. Wang. Irvsp: to obtain irreducible representations of electronic states in the VASP. Comput. Phys. Comm. 261, 107760 (2021). https://doi.org/10.1016/j.cpc.2020.107760.

And the code is provided on github: https://github.com/zjwang11/irvsp