6. Tutorial

This is a minimal end-to-end example (film, finite displacement, RTA).

6.1. Step 1: Build a film structure

python Structure/build_and_relax_prim.py --model film --thick 8 --vac 15

This writes:

  • Structure/POSCAR

6.2. Step 2: Create an input file

Create input.txt:

--poscar      Structure/POSCAR
--nep_model   NEP/Si_2025_Xuke.txt
--do_relax    false
--dim         4 4 1
--mesh        21 21 1
--temps       100 1000 100
--fc2fc3      true
--use_hiphive false
--method      rta
--wigner      true

6.3. Step 3: Run workflow

python nepkappa.py input.txt

Typical outputs:

  • fc2.hdf5

  • fc3.hdf5

  • kappa-m21211.hdf5

The exact kappa filename depends on the mesh.

For details on reading kappa-m*.hdf5 files, please refer to the phono3py HDF5 documentation.

6.4. Step 4: Plot examples

python path/plot_film.py

This generates:

  • path/Si_film_1nm_4panel.pdf

6.5. Notes

  • Example plotting scripts are templates for your own data.

  • For your own results, copy and edit script paths accordingly.