Guan is an open-source python package developed and maintained by (Ji-Huan Guan, 关济寰). With this package, you can calculate band structures, density of states, quantum transport and topological invariant of tight-binding models by invoking the functions you need. Other frequently used functions are also integrated in this package, such as file reading/writing, figure plotting, data processing.

The primary location of this package is on the current website The latest version is “guan-0.0.168”, updated on April 25, 2023. You can install (upgrade) this package to the latest version by executing the following command in a terminal:

pip install --upgrade guan


import guan

About this package:

  1. The original motivation of this project is for self use. Based on this project, the frequent functions can be imported by “import guan” instead of repeated copies and pastes. You can also install and use this open-source package if some functions are helpful for you. If one function is not good enough, you can copy the Source Code and modify it. You can also feed back to The modifications and supplements will be in the following updated version.
  2. All realizations of this package are based on functions without any class, which are concise and convenient. The boring document is omitted and you have to read the Source Code for details if it is necessary. Nevertheless, you don’t have to be worried about the difficulty, because all functions are simple enough without too many prejudgments and the variable names are written commonly as far as possible for the easy reading.
  3. Before the function calling in your project, you are recommended to briefly read the Source Code to know the specific formats of input and output about the function. Applying functions mechanically may cause errors. Notice that as the package is developed, the function names may be changed in the future version. Therefore, the latest API Reference is important and helpful.

License: GNU General Public License v3 (GPLv3).

Summary of API Reference:

  1. basic functions
  2. Fourier transform
  3. Hamiltonian of finite size systems
  4. Hamiltonian of models in the reciprocal space
  5. band structures and wave functions
  6. Green functions
  7. density of states
  8. quantum transport
  9. topological invariant
  10. read and write
  11. plot figures
  12. data processing
  13. file processing
  14. others

All files can be read here or downloaded from GitHub or Cloud.

Citation: There is no official paper related to this package temporarily, but you can cite one or all of the following papers instead which are the motivation of this project (e.g., calculating the scattering matrix), if this package is greatly helpful for your research.

Acknowledgments: University of Chinese Academy of Sciences | Institute of Semiconductors, CAS | The State Key Laboratory of Superlattices and Microstructures | Beijing Academy of Quantum Information Sciences | National Natural Science Foundation of China | Shu-Shen Li | Kai Chang | Yan-Yang Zhang | Qing-Feng Sun | Hai-Wen Liu | Hua Jiang | et al.