PhonopyCalculation#

The phonopy of Phonopy computes phonon properties within the harmonic approximation, using either finite difference of forces or already computed second-order force constants with other methods (e.g. density functional perturbation theory, DFPT). Examples of these properties include phonon band structure, Helmoltz free energy, thermal capacity, and so on. For a detailed list of such properties, please consult the official documentation.

Plugin class

PhonopyCalculation

Plugin entry point

phonopy.phonopy

How to launch a phonopy calculation#

Below is a basic example of how to run a phonopy calculation through the PhonopyCalculation plugin that computes the phonon band structure of an fcc silicon crystal.

Note that you may have to change the name of the code that is loaded using load_code.

How to define input file parameters#

The phonopy code supports many parameters that can be defined through the input file, as shown on the official documentation. The parameters are simple tags that activate a particular post-processing.

parameters = {'bands':'auto'}

The parameters dictionary should be wrapped in a Dict node and assigned to the parameters input of the process builder:

from aiida.orm import Dict, load_code
builder = load_code('phonopy').get_builder()
parameters = {
    ...
}
builder.parameters = Dict(parameters)

Warning

There are a number of input parameters that cannot be set, as they will be automatically set by the plugin based on other inputs. Defining them anyway will result in an exception when launching the calculation.

How to add extra settings#

You can specify extra settings to set the fine details of the calculations. These are:

  • symmetrize_nac: bool; it symmetrizes the dielectric and Born effective charges, and applies sum rules

  • factor_nac: float; it will use this conversion factor in the non-analytical correction

  • subtract_residual_forces: bool; it will subtract the forces of the pristine supercell

For example:

builder.settings = Dict({'symmetrize_nac': True})

How to retrieve animation files#

The PhonopyCalculation plugin will retrieve the most important and common output files by default. To retrieve animation output files, specify the keep_animation_files key in the settings input:

builder.settings = Dict({'keep_animation_files': True})