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

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smiri
Posts: 4
Joined: Thu Oct 26, 2023 2:16 am

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

Post by smiri » Thu May 09, 2024 2:48 am

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
Adlen Smiri
Postdoctoral Researcher
MathAM-OIL AIST, Tohoku University, Sendai, Japan

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palful
Posts: 75
Joined: Tue Jan 26, 2016 11:23 am
Location: Modena and Milan

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

Post by palful » Thu May 09, 2024 4:47 pm

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
Dr. Fulvio Paleari
S3-CNR Institute of Nanoscience and MaX Center
Modena, Italy

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