Yambo Community Forum

Dear Yambo developers and users

1. Dose Yambo support the G0W0 calculation for 2D metallic or half-metallic systems for example transition-metal dichalcogenides (including d valence orbitals)? Doesn't discontinuity of the band occupation crossing the fermi surface in these systems cause a problem in Yambo GW calculations?
2. Are the GW calculations for metallic and half-metallic systems (including d valence orbitals) the same as for semiconductor systems or need to consider other technical issue or additional input variable?
3. Can you please introduce an article that did GW calculation for a 2D metal or half-metal by Yambo?

Thanks a lot

Dear anonymous user,
please sign your post with your full name and affiliation, this is a rule of the forum.

You can perform GW calculation for these systems, anyway at the moment the Drude term it is not included in the screening.
This makes the calculation harder to converge with respect the k point grid.
We are working on the inclusion of the metallicity in the screening for 2D system, at the moment this development it is not yet available, and it will be hopefully available soon and this will allow to accelerate the convergence with respect the k points.

You need to perform the calculation as usual, Yambo will take care of the fractional occupation number across the Fermi level, there is not discontinuity assuming you use a smearing in your ground state calculation. But again, the convergence wrt the k points could be very hard!

In this paper you can find a GW calculation of a metallic 1D system (Phys. Rev. B 101, 161410(R)), in this case the metallicity was treated with an ad-hoc implementation for the BSE kernel, but not for the GW part (see support. info.).

Best,
Daniele

Dear Daniele

Thank you very much for your quick reply.