My Community

Dear VASP-Community,
I am using VASP 6.4.0 (compiled with HDF5 support) to find electron-phonon coupling matrix elements using the VASP+phelel approach. I am facing some difficulties due to the non-working of some INCAR tags (ELPH_PREPARE). Consequently, the vaspout.h5 file does not contain the following fields which are required by the phelel code :
1. ["results/potential/total"],
2. ["results/paw/lmdim"][()],
3. ["results/paw/ldim"][0],
4. ["/results/paw/lmax"][:],
5. ["/results/paw/lps"][:],
6. ["/results/paw/dij"][:], and
7. ["/results/paw/qij"][:]
Using VASP Wiki, I have learned that I may set LVTOT =. TRUE. and obtain the LOCPOT file which corresponds to the same quantity as in ["results/potential/total"] of the vaspout.h5, also I have obtained lmdim, ldim, lmax, lps, scalars/arrays using the information in POTCAR and OUTCAR files.

I have 2 questions:

1) I request the learned moderator/other experienced community members to help me by confirming if I have correctly updated the quantities lmdim,ldim,lmax and lps in the modified vaspout.h5 files.:
lmdim= 13
ldim = [5]
lmax = [5,5,5,5,5,5,5,5]
lps = [[0,0,1,1,2,3],[0,0,1,1,2,3]]

2) From the OUTCAR files, I understand that the lmdim in each calculation is 13. In addition, according to the comments in the ‘read_PAW_Dij_qij_vaspouth5’ function definition in ‘file_IO.py’ (part of phelel code), I understand that the expected dimensions for dij and qij matrices for each atom is (lmdim,lmdim). However, I am facing difficulty in finding these PAW strength parameters dij and the augmentation charge parameters qij. I would deeply appreciate help.

------------------Contents of the attached directory:
1. 15_Jan_test_calc_1_1_1_supercell_PbTe: Contains the calculation folders disp-000, disp-001,disp-002, disp-003, and disp-004. The original vaspout.h5 files are named org_vaspout.h5, the file named vaspout.h5 corresponds to the modified version.
2. The source code in ‘file_IO.py’: I have highlighted the required quantities from vaspout.h5. The required quantities available in original vaspout.h5 are in green, the inputs which I have been able to update are in blue, and the ones for which I have not found yet (dij and qij matrices) are in red.
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Thanking you.

Dear mukhtiyar_singh,

thank you for reaching out to us on the official VASP forum.

I cross-checked your calculation and I can confirm that the tag ELPH_PREPARE works perfectly fine on VASP 6.5.0. The tag does not work in 6.4.0 because it was not part of this version, and the feature is new in 6.5.0. Do you have access to 6.5.0? This would be the easiest way for you to make the interface to phelel work. We will add some disclaimer on the wiki for these tags that this requires 6.5.0.

Best regards,
Alex H.