Auto-kappa is an automated workflow tool for performing first-principles calculations of anharmonic phonon properties, including

• lattice thermal conductivity,
• mode-dependent phonon lifetimes,
• three-phonon and four-phonon scattering,

using VASP and ALAMODE.
It provides a streamlined pipeline that generates input files, submits calculations, checks convergence, and post-processes results automatically.

Users of auto-kappa need to install VASP and ALAMODE in advance, while the required Python libraries are installed automatically along with auto-kappa.

• VASP : 6.3.0 or later
• ALAMODE : 1.4 or 1.5 (1.5 recommended) *
• [Optional] anphon : 1.9.9 (required for four-phonon scattering)
• Python : 3.9 or later
• Phonopy : 2.43.2 or former
• ASE
• Pymatgen
• Spglib
• Custodian

* Note: The force constant file format in ALAMODE 1.4 is incompatible with that of version 1.5. Therfore, version 1.5 is recommended.

Follow these steps to install the package:

1. git clone https://github.com/masato1122/auto-kappa.git
2. cd ./auto-kappa
3. sh install.sh

After installation, ensure that the akrun command is available. You can view a description of the input parameters by running akrun -h.

You can perform a simple calculation following the steps below. Please refer to example jobs in auto_kappa/examples and the manual for details.

1. Set the VASP_PP_PATH environment variable so that ASE can locate VASP pseudopotential files: (Pseudopotential with ASE)

ASE expects the pseudopotential files to be in ${VASP_PP_PATH}/potpaw_PBE/{element name}.

2. Prepare a structure file, e.g., POSCAR.Si
3. Run the following command: akrun --file_structure POSCAR.Si --outdir Si.

You can view the available options by running akrun -h as well as in the manual. Frequently used commands are listed below.

• file_structure: Structure file name. Different formats, including POSCAR and CIF, are accepted.

• outdir: Name of the output directory

• mpirun: MPI command [Default: mpirun]

• nprocs: Number of processes for the calculation [Default: 2]

• command_{vasp/vasp_gam/alm/anphon/anphon_ver2}: Command to run VASP, alm, and anphon [Default: vasp, vasp_gam, alm, anphon, anphon.2.0]

• volume_relaxation: Perform relaxation calculations using the Birch-Murnaghan equation of state [Default: 1]

• analyze_with_larger_supercell: Use a larger supercell when imaginary frequencies appear [Default: 0]

• max_natoms: Maximum number of atoms in the supercell used for the force constant calculation [Default: 150]

• nmax_suggest: Maximum number of displacement patterns for the finite-displacement method. If the number of generated patterns exceeds this value, the LASSO regression approach will be applied [Default: 100].

• scph: Flag for considering phonon renormalization using the self-consistent phonon (SCPH) approach [Default: 0]

• four: Flag for considering four phonon scattering. The "command_anphon_ver2" option must be set properly. [Default: 0]

For more details on auto-kappa, please visit the following webpage: HERE.

If you use auto-kappa, please cite the following paper, along with any related papers listed in the references:

• M. Ohnishi et al., "Database and deep-learning scalability of anharmonic phonon properties by automated brute-force first-principles calculations", arXiv:2504.21245 (2025).

• ALAMODE: T. Tadano, Y. Gohda, and S. Tsuneyuki, J. Phys.: Condens. Matter 26, 225402 (2014).

• ALAMODE (SCP): T. Tadano and S. Tsuneyuki, Phys. Rev. B 92, 054301 (2015).

• VASP: G. Kresse, and J. Furthmuller, Phys. Rev. B 54, 11169-11186 (1996).

• Spglib: A. Togo, K. Shinohara, and I. Tanaka, Sci. technol. adv. material, Meth. 4, 1 (2025).

• SeeK-path: Y. Hinuma, G. Pizzi, Y. Kumagai, F. Oba, and I. Tanaka, Comp. Mat. Sci. 128, 140 (2017).

• Phonopy: A. Togo and I. Tanaka, Scr. Mater., 108, 1-5 (2015).

• Pymatgen and Custodian: S. P. Ong et al., Comp. Mater. Sci. 68, 314-319 (2013).

• ASE: A. H. Larsen et al., J. Phys.: Cond. Matter 29, 273002 (2017).

• Tianqie Deng, Michimasa Morita, Wei Nong, Masato Ohnishi, Terumasa Tadano, Pol Torres, Zeyu Wang

(alphabetical order)