Inquiry into extracting eps_GG'(q) using Yambopy obtained via RPA plus Truncated Coulomb Interaction.

[smiri]

Hi everyone,

I am interested in studying the dielectric properties by reading and analyzing the data contained in the Yambo databases of RPA calculations including a coulomb truncation technique. Therefore, I am curious about the possibility of extracting the static dielectric function matrix eps_GG'(q) (or eps_GG'(q)^-1) using Yambopy?

A quit similar thing was done for BSE calculations where the eps_00(q)^-1 was plotted:
https://www.yambo-code.eu/wiki/index.ph ... ption_(BN)

Thank you in advance for your time and assistance.
Best regards,
Smiri Adlen

[palful]

Dear Adlen,

You can absolutely do this provided that you have the ndb.em1s* databases and the ns.db1 database from the SAVE directory.

Yambopy has a dedicated class for this called YamboStaticScreeningDB. It loads epsilon^-1_GG'(q) and allows for the plotting of related quantities.

This class does not yet have a tutorial, but I am attaching here a script demonstrating how to load the epsilon and to plot various quantities. For example, you could plot epsilon^{-1}_00(q) along |q| or along a specific q-direction to start familiarising with it.

The YamboStaticScreeningDB.X attribute is the one containing the values of (vXv)_GG' which are loaded from the database. v is the Coulomb potential (truncated or not) and X is the RPA response function.

Keep in mind that epsilon^-1_GG'(q) = 1+(vXv)_GG' (there is a function to automatically construct that) and that epsilon_GG'(q) requires the inversion of the tensor (so far this is done automatically only for the head of the inverse tensor that can be immediately plotted).

Cheers,
Fulvio