VASP Forum

Dear support team,

I am using vasp 6.5.0, phelel_param.hdf5 not getting generate with ELPH_POT_GENERATE = .TRUE.. Do I need to add a tag while compiling to enable e-ph calculations?

Thanks,
Shweta

Dear Shweta,

Thank you for reaching out to us on the VASP Forum. First off, please upload all relevant files as a .zip according to our posting guidelines as found here.
Generally, electron-phonon computations only work while HDF5 support is enabled, as explained here.

Best regards,

Dear Max,

I am attaching OUTCAR. I already have HDF5 support enabled, and vaspout.h5 is always written. I do not understand why the ELPH tag is not read.

Thank you,

Dear Shweta,

Thank you for the OUTCAR. After taking a closer look, I think I have identified the likely culprits.

• In VASP 6.5.0, there was a bug where ELPH_POT_GENERATE only worked when ELPH_POT_FFT_MESH is also given. That bug is fixed in VASP 6.5.1 - therefore, please either upgrade to VASP 6.5.1 OR manually specify the info of the unit cell used for the subsequent electron-phonon step:

  • ELPH_POT_FFT_MESH (with exactly the FFT mesh of the unit cell (NGX, NGY, NGZ))
  • ELPH_POT_LATTICE (with the lattice vectors of the unit cell)

• In addition, ELPH_POT_GENERATE should not be combined with LCALCEPS or LCALCPOL. Similarly, EFIELD_PEAD should also be omitted for generating the phelel_param.hdf5.

Please implement these changes next, and let me know if that resolves the problem.

Thank you!