Bandstructure of B-P nanosheet not calculated correctly

[sguha]

I am trying to calculate the bandstructure of Boron phosphide nanosheet, however I am getting 0 ev direct bandgap which is not correct.
I am attaching the script file, can someone please help me?
Reference: H. Li, Y. Zhou, and J. Dong, ‘First-Principles Study of the Electron Transport Properties of Graphene-Like 2D Materials’, Nanoelectronics and Materials Development. InTech, Jul. 27, 2016. doi: 10.5772/64109.

[Anders Blom]

The paper you refer to is done with DFT, but your model in the script is using an extended Huckel model. That might work, sometimes, and would save a lot of time, however as your test shows, for this system the Huckel parameters do not give the correct band structure etc for B-P, thus it cannot be used.

You might try other parameters such as the Muller or Hoffmann models, and also it will be important to perform the calculations self-consistently since there will be significant charge transfer between B and P atoms (might try that with Cerda parameters too but I doubt it will work, as the two parameter sets you are trying to mix come from fits to AlP and BN).

I think your main option will be DFT in this case.

[sguha]

Thank you. After doing DFT, I got closely accurate bandgap of 0.89ev.