I am doing DFPT calculations using VASP+Phonopy. To plot phonon band structure, I need a band.conf file in which we need to provide primitive axis. There is an option to use --pa=auto but in my case, it is not working, or maybe for DFPT, we need to supply a proper primitive axis.

Is there any way or code using which we can know the primitive axis of any system?

POSCAR for my system is mentioned below:

     5.2830000000000004    0.0000000000000000    0.0000000000000000
     0.0000000000000000    5.2830000000000004    0.0000000000000000
     0.0000000000000000    0.0000000000000000   20.0000000000000000
   Ta   N 
     2     4
  0.0000000038778781 -0.0000000040248837  0.4999999999997483
  0.5000000098083184  0.4999999954548999  0.4999999998722517
  0.1428654795841584  0.6428651637231821  0.5338481609868386
  0.8571345120369003  0.3571348472078131  0.5338481661924134
  0.6428651606314468  0.8571345203839439  0.4661518370931707
  0.3571348450612953  0.1428654882550420  0.4661518358555774
  • $\begingroup$ The documentation says that the primitive axis is the transformation matrix from the primitive cell to the supercell and that it is optional. Are you wanting help defining this matrix using software or help with getting the automatic primitive cell detection in phonopy to work? If it’s the latter, maybe a description of the error message or a minimal example that demonstrates the issue would help get an answer. $\endgroup$ Commented Aug 27, 2021 at 4:13
  • $\begingroup$ Yes, I want to define pimitive_axis to get the phonon band structure. Please let me know if I need to supply some information from my side. $\endgroup$
    – astha
    Commented Aug 27, 2021 at 4:25
  • $\begingroup$ Are you sure that your cell is not already a primitive cell? $\endgroup$
    – ProfM
    Commented Aug 29, 2021 at 7:54
  • $\begingroup$ Yes, it is already a primitive cell. This is just an example. I am focusing to get a permanent solution to get the primitive axis to get the phonon band structure of any structure. $\endgroup$
    – astha
    Commented Aug 29, 2021 at 13:05
  • 1
    $\begingroup$ astha, thanks for replying to all comments so quickly! Perhaps you can put some of the code block in that comment, into the question so that it's easier for @ProfM to read? code blocks (especially long ones) tend to be displayed in a much clearer way when they're in actual posts rather than just in comments. $\endgroup$ Commented Dec 31, 2021 at 0:58


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