I was trying to make phonon dispersion using the foundational MLIPs using ASE. I wanted to see how the LO-TO splitting occurs at the GM point with these potentials.
But I find the “Current Implementation of the LO-TO splitting is currently depreciated“ in the source code. Is this issue fixed? What is the current way to get the Non-analytic corrections in the phonon dispersion?
Also, what should be the format of the json file with the Born effective charge and the dielectric tensor information?
Hi, Dominic
From what I’ve read. ASE still says the non-analytic correction for LO–TO splitting is not included in the present implementation, and read_born_charges() is still marked deprecated / likely incorrect. However, For the current workflow. I’d recommend you to use Phonopy NAC instea.d, the BORN file has 1st line = unit conversion factor, 2nd line = 3×3 dielectric tensor, then 3×3 Born charge tensors for each independent atom in the primitive cell. It just a recommendation, you should’ve tried other workflows