kappamin

A python3 code for calculations of the minimum limit to thermal conductivity

Features

• Models of the minimum limit to thermal conductivity under Cahill assumption[^1]
  • Debye model[^2]
  • BvK (Born–von Karman) model[^3]
  • Pei model[^4]
• Temperature-dependence
  • Finite temperature
  • Ideal infinite temperature
• Relative
  • Heat Capacity
  • Minimum mean-free-path
  • Minimum average phonon lifetime
• Running mode
  • Command line mode based on a simple configuration file (for the routine analysis)
  • Based on prepared scripts (for general researchers without programming skills)
  • Use as a python module (for expert usage)

Getting Started

In order to install the module, you need to install the dependencies first:

• python3
• numpy
• scipy

Download the package from GitHub website or using git,

git clone https://github.com/JianboHIT/kappamin.git

then run setup.py to install.

cd kappamin
python3 setup.py install

Python module kappamin will be installed if no error. In order to invoke kappamin module, you need to prepare a configuration file (see Example_Debye.txt and Example_BvK.txt in the source package).

python -m kappamin [KAPPAMIN.txt]

Here KAPPAMIN.txt indicates the filename of configuration file. It is worth mentioning that the filename is optional. If the filename is not given, the program will read the file named as KAPPAMIN.txt if it existed.

Alternately, a more convenient way to implement calculation is by an executable script (see ExceuteScript.py), then run it by python3. On Linux or Windows Terminal:

python ExceuteScript.py

On Windows, if it has been configured that the default program to open .py file is python3, you just need to move ExceuteScript.py to the directory at where the configuration file is located and double-click it to run.

Moreover, advanced users may prefer to skip the command-line interface and access the full feature set of kappamin more directly. Those wanting to use the interpolation capabilities of kappamin in their own code, or using it as part of an automated workflow, ones can see Example_AsModule.py.

Feedback and report bugs

See GitHub Issue page.

Change log

(More details see CHANGELOG)

• 2023.08.27 v0.2.0 Add Example_AsModule.py file
• 2022.10.16 v0.1.1 Fix crucial bug in Pei model
• 2022.10.16 v0.1.0 Develop Debye, BvK, and Pei models
• 2022.10.06 v0.0.1 Initial package version

Reference

[^1]: D.G. Cahill, R.O. Pohl, Heat flow and lattice vibrations in glasses, Solid State Communications, 70 (10) (1989) 927-930. https://doi.org/10.1016/0038-1098(89)90630-3

[^2]: P. Debye, Zur theorie der spezifischen wärmen, Annalen Der Physik, 344 (14) (1912) 789-839. https://doi.org/10.1002/andp.19123441404

[^3]: M. Born, T. Von Karman, Vibrations in space gratings (molecular frequencies), Z Phys, 13 (1912) 297-309.

[^4]: Z. Chen, X. Zhang, S. Lin, L. Chen, Y. Pei, Rationalizing phonon dispersion for lattice thermal conductivity of solids, National Science Review, 5 (6) (2018) 888-894. https://doi.org/10.1093/nsr/nwy097