the meaning of GphBRnge

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will
Posts: 31
Joined: Thu Feb 16, 2017 2:26 pm
Location: Beijing

the meaning of GphBRnge

Post by will » Tue Jan 22, 2019 1:56 pm

Hello all,
I want to know what GphBRnge means. I can't find an explanation on the Yambo website. Should I converge it? By the way, when I increase it, the vbm or cbm energy correction oscillates significantly, and they don't seem to converge at all. I am really confused. thank you very much!

Xiaowei
Xiaowei Zhang
Ph.D. Student
ICQM, Peking University
Beijing, China

elena.cannuccia
Posts: 24
Joined: Tue Oct 11, 2016 10:58 am

Re: the meaning of GphBRnge

Post by elena.cannuccia » Tue Jan 22, 2019 6:26 pm

Dear Xiaowei,

GphBRnge has been introduced in order to check the effect of different phonon branches groups (acoustic, optic) on the renormalization of the electronic gap..

You have to include all of them.

Elena

will
Posts: 31
Joined: Thu Feb 16, 2017 2:26 pm
Location: Beijing

Re: the meaning of GphBRnge

Post by will » Wed Jan 23, 2019 3:59 am

Dear Elena,
Thank you for your reply. I read the source file. GphBrnge seems to be the electronic band range when calculating the electron-phonon self-energy. Is this correct?
Xiaowei
Xiaowei Zhang
Ph.D. Student
ICQM, Peking University
Beijing, China

elena.cannuccia
Posts: 24
Joined: Tue Oct 11, 2016 10:58 am

Re: the meaning of GphBRnge

Post by elena.cannuccia » Thu Jan 24, 2019 10:22 am

Dear Xiaowei,

sorry it is my fault, I was thinking of ElPhModes.

Yes, GphBRnge is the number of electronic bands that you want to include in the calculation of band gap renormalization for example.
In principle it is a parameter whose convergence must be checked. In practice it comes from a previous quantum espresso nscf calculation.

So at the level of the tutorial you have to play with the value which automatically comes out when you prepare your input file.

Elena

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