non-linear response

Deals with issues related to computation of optical spectra, in RPA (-o c) or by solving the Bethe-Salpeter equation (-o b). Includes local field effects, excitons, etc.

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sitangshu
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Joined: Thu Jan 05, 2017 8:08 am

Re: non-linear response

Post by sitangshu » Wed Jul 03, 2019 9:41 am

I will send in your email...

With regards,
Sitangshu
Sitangshu Bhattacharya
Indian Institute of Information Technology-Allahabad
India
Web-page: http://profile.iiita.ac.in/sitangshu/
Institute: http://www.iiita.ac.in/

sitangshu
Posts: 119
Joined: Thu Jan 05, 2017 8:08 am

Re: non-linear response

Post by sitangshu » Mon Oct 21, 2019 7:33 am

Dear Professor Claudio

I hope you are fine. Just wanted to share some news with you regarding our latest work on ab initio non linear optical responses in monolayer GaAs:

https://arxiv.org/abs/1910.08443

I hope you will like this.....

With regards

Sitangshu
Sitangshu Bhattacharya
Indian Institute of Information Technology-Allahabad
India
Web-page: http://profile.iiita.ac.in/sitangshu/
Institute: http://www.iiita.ac.in/

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claudio
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Re: non-linear response

Post by claudio » Mon Oct 21, 2019 8:39 am

Very good!

Claudio
Claudio Attaccalite
[CNRS/ Aix-Marseille Université/ CINaM laborarory / TSN department
Campus de Luminy – Case 913
13288 MARSEILLE Cedex 09
web site: http://www.attaccalite.com
Freely download scientific books from: http://www.freescience.info

Marzieh
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Joined: Sun Feb 28, 2021 8:46 pm

non-linear response

Post by Marzieh » Mon Mar 29, 2021 3:51 pm

Dear Claudio,

How to get all non zero components of SHG spectra? Which variables is for this goal?
For changing frequencies I should change NLEnSteps, right?

Best,
Marzieh
Marzieh Ghoohestani, PhD
Institute of Condensed Matter and Nanosciences,
Université Catholique de Louvain,
8 Chemin des étoiles, 1348 Louvain-la-Neuve, Belgium
https://uclouvain.be/en/directories/marzieh.ghoohestani

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claudio
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Re: non-linear response

Post by claudio » Mon Mar 29, 2021 9:06 pm

Dear Marzieh

>How to get all non zero components of SHG spectra? Which variables is for this goal?

you select the cartesian direction of the probe field with the variable and then measure the response
in the direction that you want. For example in the AlAs tutorial

http://www.yambo-code.org/wiki/index.ph ... r_response

we put the field in the x,y direction with the input parameter

Code: Select all

% ExtF_Dir
  1.000000 | 1.000000 | 0.000000 |        # [NL ExtF] Versor
then we measure the response in the z direction. In such a way we got the X^2_{xyz}.
Notice that in the output file

Code: Select all

o.YPP-X_probe_order_2
contains also the response in the x, y direction
and therefore from the same calculation you get the X^2_{xyx}, X^2_{xyy} and X^2_{xyz}.
Some of these can be zero due to symmetry reasons. (note that due to the numerical noise the zero components may be very small but slightly different from zero).

>For changing frequencies I should change NLEnSteps, right?

Yes, this are the number of frequency steps in the energy interval between

Code: Select all

% EnRngeRt
  0.00000 | 10.00000 | eV    # Energy range
%
let me know if it is clear
best
Claudio
Claudio Attaccalite
[CNRS/ Aix-Marseille Université/ CINaM laborarory / TSN department
Campus de Luminy – Case 913
13288 MARSEILLE Cedex 09
web site: http://www.attaccalite.com
Freely download scientific books from: http://www.freescience.info

Marzieh
Posts: 23
Joined: Sun Feb 28, 2021 8:46 pm

Re: non-linear response

Post by Marzieh » Mon Mar 29, 2021 9:50 pm

Dear Claudio,

Thank you for your explanation.

Could you please explain more to make clear for me?
For example which ExtF_Dir are for the X^2_{xyx}, X^2_{xyy} and X^2_{xyz} respectively?

Can we have all non zero components in a calculation or have to calculate separately?

Best,
Marzieh
Marzieh Ghoohestani, PhD
Institute of Condensed Matter and Nanosciences,
Université Catholique de Louvain,
8 Chemin des étoiles, 1348 Louvain-la-Neuve, Belgium
https://uclouvain.be/en/directories/marzieh.ghoohestani

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claudio
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Re: non-linear response

Post by claudio » Mon Mar 29, 2021 10:26 pm

Ok,

in the X^2 you have three direction, two of the incoming fields and one where you measure the response

The field direction determines the first two components and the response the last one.
For example if you set in Yambo field direction

1.0 | 0.0 | 0.0 | ---> you calculate all components X^2_{xx*}
0.0 | 1.0 | 0.0 | ---> you calculate all components X^2_{yy*}
0.0 | 0.0 | 1.0 | ---> you calculate all components X^2_{zz*}

1.0 | 1.0 | 0.0 | ---> you calculate all components X^2_{xy*}
1.0 | 0.0 | 1.0 | ---> you calculate all components X^2_{xz*}
0.0 | 1.0 | 1.0 | ---> you calculate all components X^2_{yz*}

the * correspond to the different direction in the response file o.YPP-X_probe_order_2.

In the o.YPP-X_probe_order_2 you have seven columns:

The first is the energy,
the 2nd and 3rd columns are the imaginary and real part of X^2_{**x}
the 4th and 5th columns are the imaginary and real part of X^2_{**y}
the 6th and 7th columns are the imaginary and real part of X^2_{**y}

where the ** are the direction of the incoming field, see above.

IF wan
Claudio Attaccalite
[CNRS/ Aix-Marseille Université/ CINaM laborarory / TSN department
Campus de Luminy – Case 913
13288 MARSEILLE Cedex 09
web site: http://www.attaccalite.com
Freely download scientific books from: http://www.freescience.info

Marzieh
Posts: 23
Joined: Sun Feb 28, 2021 8:46 pm

Re: non-linear response

Post by Marzieh » Mon Mar 29, 2021 10:58 pm

Dear Claudio,
Your explanation was very instructive for me to follow the next steps.
Thank you.
Best,
Marzieh
Marzieh Ghoohestani, PhD
Institute of Condensed Matter and Nanosciences,
Université Catholique de Louvain,
8 Chemin des étoiles, 1348 Louvain-la-Neuve, Belgium
https://uclouvain.be/en/directories/marzieh.ghoohestani

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claudio
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Re: non-linear response

Post by claudio » Tue Mar 30, 2021 7:45 am

Dear Marzieh

I added this explanation to the tutorial

http://www.yambo-code.org/wiki/index.ph ... fferent_X2

best
Claudio
Claudio Attaccalite
[CNRS/ Aix-Marseille Université/ CINaM laborarory / TSN department
Campus de Luminy – Case 913
13288 MARSEILLE Cedex 09
web site: http://www.attaccalite.com
Freely download scientific books from: http://www.freescience.info

Marzieh
Posts: 23
Joined: Sun Feb 28, 2021 8:46 pm

Re: non-linear response

Post by Marzieh » Wed Mar 31, 2021 9:32 am

Dear Claudio,

I have several questions.

If I have understood correctly, at the first we should use converged abinit( pwsf) files (with respect ecut, nband and k point). Then we have to do convergence yambo calculation only with respect NLnabd, right?

To get SHG responses at zero frequency, can we put like this?
% NLEnRange
0.000001 | 5.000000 | eV # [NL] Energy range
or
change NLEnSteps variable?

For getting the SHG responses to laser 1064 nm, how to do?

Best,
Marzieh
Marzieh Ghoohestani, PhD
Institute of Condensed Matter and Nanosciences,
Université Catholique de Louvain,
8 Chemin des étoiles, 1348 Louvain-la-Neuve, Belgium
https://uclouvain.be/en/directories/marzieh.ghoohestani

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