freepaths 1.0

Phonon Monte Carlo simulator

FreePATHS - Free Phonon And THermal Simulator

This Monte Carlo algorithm simulates trajectories of phonons in 3D models of nanostructures, which consists of a box with holes or pillars of various shapes. The algorithm outputs phonon trajectories, heat fluxes, temperature maps and profiles, the thermal conductivity, scattering maps and statistics and other information. See the wiki pages for the details of the simulation.

Installation

Program requires python 3. On Linux and MacOS it is probably already installed. On Windows, you may choose to install Anaconda.

Install from PyPi repository with:

pip install --upgrade freepaths

Usage

Run the program as:

freepaths your_input_file.py

In the example folder, you will find examples of the input files. Try to use one of them, for example:

freepaths simple_nanowire.py

If you wish to run it in the mean free path sampling mode to calculate the thermal conductivity, add -s flag:

freepaths -s simple_nanowire.py

However, if you simply run freepaths without specifying an input file, the program will run a demo simulation. After the simulation, see the results in a newly created Results folder.

Disclaimer

The code is still in development and provided as is. It likely contains bugs or might be inappropriate for your research. It is your responsibility to understand the underlying physics, test the code, and verify that all the equations and the code are correct. See the wiki pages and the references below for more details on the code.

References

Details of the code and examples of the output can be found in the following papers:

1. Anufriev et al. Materials Today Physics 15, 100272 (2021)
2. Anufriev et al. Nanoscale, 11, 13407-13414 (2019)
3. Anufriev et al. ACS Nano 12, 11928 (2018)

Credits

The code has been developed by Roman Anufriev in Nomura lab at the University of Tokyo in 2018-2022. If you would like to use this code for your research, please cite the papers above, if it is appropriate.

Acknowledgments

Development of this code was funded by the following grants:

• PRESTO JST (No. JPMJPR19I1)
• CREST JST (No. JPMJCR19Q3)
• Kakenhi (15H05869, 15K13270, and 18K14078)
• Postdoctoral Fellowship program of Japan Society for the Promotion of Science.