Initial layer position for 2D Coulomb truncation

[Bo Peng]

Ciao,

I am running the truncated Coulomb potential for 2D materials. If I change the initial position of the layer in QE, e.g. moving a graphene layer from z=0 to z=0.5 (in direct coordinate), the GW corrections have a difference about 5-15 meV. Is this something that I should worry about? Or I should just keep the atomic positions in z=0, as demonstrated in the tutorial on monolayer BN? Thank you in advance!

Best regards,
Bo

[Daniele Varsano]

Dear Bo,
actually, this should not happen, and if I'm not wrong the potential component (ndb.cutoff) should be the same in the two cases, and the reason of the discrepancy should be ascribed to something else. Anyway, if you are not interested in extreme accuracy, the difference is rather small.
Also, we have developed a much better way to treat 2D systems, it will be released very soon and the actual 2D cutoff will be dismissed.

Best,
Daniele

[Bo Peng]

Thank you Daniele! Look forward to the new release!