Obtaining Atomic Basis Sets for Materials in Source Code

[sumeyyekaragul]

Where can atomic basis sets for materials be obtained from in the source code? We need basis atomic set for our research project. Where are the basis sets you mentioned in this link: https://docs.pybinding.site/en/stable/intro.html?highlight=basis#background .
Can you help with this?

[BertJorissen]

It depends on which tight-binding model is used. In the current implementation of Pybinding, only orthogonal basis sets are allowed. For graphene for example, this will be a pz-orbital per onsite. In a TMD, these van be different d- and p-orbitals. Other models mainly use the famous Slater-Koster approach (definitely read it 😉).

I do not understand what you want to see; do you want to know which model is used or to construct a model yourself (or something else)?
Be aware that Pybinding doesn't construct the parameters and hopping energies for the model itself. Unlike in DFT codes, you can't just mention a material in the a starting script. You have to implement the model yourself. There are some models available in the materials repository that you can use. In the source files there are some citations to the papers used to implement the model. Pybinding mainly specializes in creating complex Hamiltonians and giving numerical tools to calculate physical properties. There are other software programs like KITE and tb-studio that can calculate larger structures or obtain the parameters required to create a new model (though we're working to also implement these in a future release of pybinding).

We are working on a new release. If you encounter installation problems, you can install my development version from the test pypi with first running 'pip install scipy numpy matplotlib pytest' and then 'pip install -i https://test.pypi.org/simple/ pybinding'.
Best
Bert

[sumeyyekaragul]

We would like to thank you for four detailed explanations. We currently try to add models for III-V semiconductors to pybinding materials repo. And we would like to implement them into pybinding. We also would like to thank you and your group for this nice library and tool. We definitely will read the paper you have mentioned.

Best regards,