mirror of https://github.com/phonopy/phonopy.git
52 lines
2.0 KiB
ReStructuredText
52 lines
2.0 KiB
ReStructuredText
.. _dftbp_interface:
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DFTB+ & phonopy calculation
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=========================================
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How to run
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-----------
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DFTB+ phonon band structures are created as follows:
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1) Create a DFTB+ input file dftb_in.hsd that is set up to perform a
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single-point energy and force calculation for a structure which is named
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``geo.gen``. The dftb_in.hsd file should turn on force evaluation by setting
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``CalculateForces = Yes`` in its analysis block, and write the tagged results
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by enabling ``WriteResultsTag = Yes`` in its options.
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2) Generate the the required set of structures and the ``phonopy_disp.yaml``
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file by issuing the command ::
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% phonopy -d --dim="4 4 4" --dftb+
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This example builds 4 x 4 x 4 supercell files. The undistorted supercell is
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stored in ``geo.genS``, while the required displacements are stored in files
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matching the pattern ``geo.genS-*``. Note that you have to increase the
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supercell dimension until you reach convergence of the band structure.
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2) For each each ``geo.genS-*`` structure perform a DFTB+ calculations,
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retaining the resulting ``results.tag`` file.
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3) Create the ``FORCE_SETS`` file with the command ::
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% phonopy -f disp-*/results.tag --dftb+ ...
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Where the location of all of the ``results.tag`` files is given on the
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command line. To run this command, the ``phonopy_disp.yaml`` file has to be
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located in the current directory, because the atomic displacements are
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written into the FORCE_SETS file.
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4) Create a ``band.conf`` file to specify the path in the Brillouin zone you are
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interested in (see the phonopy documentation). Then post-process the phonopy
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data, either in the settings file (DIM) or by providing the dimensions of the
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the supercell repeat on the command line ::
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% phonopy -p band.conf --dim="4 4 4" --dftb+
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5) Create a band structure in gnuplot format ::
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% phonopy-bandplot --gnuplot band.yaml > band.dat
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All major phonopy options should be available for the DFTB+ interface.
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