Thermal Transport with FHI-vibes

The tutorial was prepared by Shuo Zhao, with the support of Konstantin Lion and Christian Carbogno

This tutorial showcases the ab initio calculation of thermal transport from a non-perturbative method (Green-Kubo theory) and a perturbative method (Boltzmann transport theory).

The methods are implemented in FHI-vibes -- a integrated workflow Python package build on the top of the atomic-simulation environment (ASE) and utilizes the Phonopy along with Phono3py for the vibrational analysis of periodic systems. It is tightly integrated with FHI-aims to perform energy, force, and stress calculations, but extending the functionality to any calculator available via ASE is straightforward.

You can find all data and scripts required for this tutorial here:

https://gitlab.com/FHI-aims-club/tutorials/thermal-transport-with-fhi-vibes

Please first clone this repository to your local machine or compute cluster (please read the Preparations section for more details).

Outline

This tutorial will cover the basic concept of phonons and introduce both perturbative and non-perturbative approaches for thermal transport. The strongly anharmonic CuI bulk system will be used as an example throughout this tutorial.

1. Preparations

2. Fast Track Tutorial

3. Phonons

   1. Theory: Harmonic vibrations
   2. Exercise: Phonon dispersion

4. Perturbative Approach

   1. Theory: Boltzmann Transport Equation
   2. Exercise: Thermal conductivity from BTE

5. Non-perturbative Approach

   1. Theory: ab initio Green Kubo
   2. Exercise: Thermal conductivity from aiGK

Acknowledgments

The tutorial is prepared according to F. Knoop, T. A. Purcell, M. Scheffler, and C. Carbogno, Phys. Rev. Lett. 130, 236301 (2023) and F. Knoop, M. Scheffler, and C. Carbogno, Phys. Rev. B. 107, 224304 (2023). Thanks to Florian Knoop for kindly providing the aiMD trajectoties of CuI and feedbacks to this tutorial. Thanks to James Green for improving the text and providing feedbacks to this tutorial.