exciting & phonopy calculation

Supported exciting tags

Phonopy can currently process the geometric section of the input file. Currently, the following parameters/elements are ignored when generating input files:

autormt, autormtscaling, cartesian, epslat, primcell, tshift, stretch, fixrmt, rmt, LDAplusU, dfthalfparam, shell

If any of these are required for your calculations, they must be manually re-added by the user after processing. Note that although it is possible to process files where atomic positions are given in Cartesian coordinates, the generated files will always use reduced (fractional) coordinates. In addition, tshift will be set to false for consistency with the input file. For more information, see: https://exciting-code.org/.

How to run

A procedure of exciting-phonopy calculation is as follows:

1. Read an exciting input file and create supercells with exciting_mode option:

   % phonopy-init --exciting -d --dim="2 2 2"
   

   In this example, 2x2x2 supercells are created. supercell.xml and supercell-xxx.xml (xxx are numbers) give the perfect supercell and supercells with displacements, respectively. In these supercell files, lines only relevant to crystal structures are generated. phonopy_disp.yaml is also created. This file contains information on displacements. Put those files in folders 001 002 ... and create a symbolic link called input.xml to those. Morever, if needed copy the species files,

2. Calculate forces on atoms in the supercells with displacements. Calculation block groundstate have to be added to each supercell.xml file.

3. Create FORCE_SETS by

   % phonopy-init --exciting -f 001/INFO.OUT 002/INFO.OUT  ...
   

   To run this command, phonopy_disp.yaml has to be located in the current directory because the atomic displacements are written into the FORCE_SETS file.

4. Run post-process of phonopy. Crystal structure and calculator interface are read from phonopy_disp.yaml:

   % phonopy -p band.conf
   

   or:

   % phonopy [other-OPTIONS] [setting-file]