1. Introduction

NEP-kappa is a workflow for lattice thermal conductivity calculations.

It combines:

  • NEP for structure relaxation and force evaluation

  • Finite Displacement or HiPhive for force-constant generation

  • phono3py for thermal conductivity calculations

1.1. Workflow

The standard workflow is:

  1. Prepare a structure

  2. Relax the structure with NEP (optional)

  3. Generate force constants

  4. Run phono3py to compute thermal conductivity

1.2. Supported routes

Two force-constant routes are supported:

  • Finite Displacement

  • HiPhive fitting

1.3. Repository layout

  • nepkappa.py: workflow entry point

  • workflow.py: core workflow implementation

  • Structure/build_and_relax_prim.py: example structure builder for Si systems

  • input_1.txt: example input for finite displacement

  • input_2.txt: example input for HiPhive

  • Example-Resuts/: example results and plotting scripts

1.4. Notes

  • The structure builder is an example script for Si systems.

  • For other materials, prepare your own structure file and pass it with --poscar.

  • Plotting scripts in Example-Resuts/ are examples only.