Abinit & phonopy calculation

Abinit & phonopy calculation#

Supported Abinit variables#

Currently Abinit variables that phonopy can read are shown below. More variables may be supported on request.

acell, natom, ntypat, rprim, scalecart, typat, xangst, xcart, xred, znucl

How to run#

A procedure of Abinit-phonopy calculation is as follows:

  1. Read an Abinit main input file and create supercells with --abinit option:

    % phonopy --abinit -d --dim="2 2 2" -c NaCl.in

    In this example, 2x2x2 supercells are created. supercell.in and supercell-xxx.in (xxx are numbers) give the perfect supercell and supercells with displacements, respectively. In these supercell files, lines only related to crystal structures are generated. phonopy_disp.yaml is also created. This file contains information on displacements. Perhaps the supercell files are stored in disp-xxx directories, then Abinit calculations are executed in these directories.

  2. Calculate forces on atoms in the supercells with displacements. Calculation specification variables have to be added to supercell-xxx.in files. Crystal structure is not allowed to relaxed in the force calculations, because atomic forces induced by a small atomic displacement are what we need for phonon calculation.

  3. Create FORCE_SETS by

    % phonopy -f disp-001/supercell-001.out disp-002/supercell-002.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. See some more detail at ABINIT interface. An example is found in example/NaCl-abinit.

  4. Run post-process of phonopy with the Abinit main input file for the unit cell used in the step 1:

    % phonopy --abinit -c NaCl.in -p band.conf


    % phonopy --abinit -c NaCl.in --dim="2 2 2" [other-OPTIONS] [setting-file]