How to deal with the Coulomb interaction in 2D systems?

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gaohan
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Joined: Sun Feb 07, 2021 3:56 am

How to deal with the Coulomb interaction in 2D systems?

Post by gaohan » Thu Mar 11, 2021 3:57 am

Dear developers,
Because my question involves equations, I attach a file.
Looking forward to your reply.
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Han Gao
School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, Shandong, China

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Daniele Varsano
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Re: How to deal with the Coulomb interaction in 2D systems?

Post by Daniele Varsano » Thu Mar 11, 2021 10:04 am

Dear Han Gao,
in reduced dimension system this is taken into account.
You need to include a truncated coulomb cutoff (see e.g. here) for a box shape. In case you have a orthorhombic cell it is suggested to use a ws shape:

Code: Select all

CUTGeo= "ws z" 
.

The the relevant quantity in output to look at is the polarisability alpha instead of the macroscopic dielectric function.

Best,

Daniele
Dr. Daniele Varsano
S3-CNR Institute of Nanoscience and MaX Center, Italy
MaX - Materials design at the Exascale
http://www.nano.cnr.it
http://www.max-centre.eu/

gaohan
Posts: 15
Joined: Sun Feb 07, 2021 3:56 am

Re: How to deal with the Coulomb interaction in 2D systems?

Post by gaohan » Fri Mar 12, 2021 1:18 pm

Dear Daniel,
Thank you for your reply.
When I include the 'Comloub' related patameters, I can get the "o-q100.eps_q*_inv_rpa_dyson" and "o-q100.alpha_q*_inv_rpa_dyson", but I can't get the output of eels spectrum
This is my input file:

Code: Select all

optics                           # [R] Linear Response optical properties
tddft                            # [R][K] Use TDDFT kernel
rim_cut                          # [R] Coulomb potential
chi                              # [R][CHI] Dyson equation for Chi.
FFTGvecs=  6               Ry    # [FFT] Plane-waves
RandQpts= 1000000                # [RIM] Number of random q-points in the BZ
RandGvec= 111              RL    # [RIM] Coulomb interaction RS components
#QpgFull                       # [F RIM] Coulomb interaction: Full matrix
% Em1Anys
 0.000000 | 0.000000 | 0.000000 |        # [RIM] X Y Z Static Inverse dielectric matrix
%
IDEm1Ref=0                       # [RIM] Dielectric matrix reference component 1(x)/2(y)/3(z)
CUTGeo= "box Z"                  # [CUT] Coulomb Cutoff geometry: box/cylinder/sphere/ws X/Y/Z/XY..
% CUTBox
  0.00000 |  0.00000 | 37.79000 |        # [CUT] [au] Box sides
%
CUTRadius= 0.000000              # [CUT] [au] Sphere/Cylinder radius
CUTCylLen= 0.000000              # [CUT] [au] Cylinder length
CUTwsGvec= 0.700000              # [CUT] WS cutoff: number of G to be modified
#CUTCol_test                   # [CUT] Perform a cutoff test in R-space
Chimod= "HARTREE"                # [X] IP/Hartree/ALDA/LRC/PF/BSfxc
NGsBlkXd= 3                Ry    # [Xd] Response block size
% QpntsRXd
 1 | 3 |                             # [Xd] Transferred momenta
%
% BndsRnXd
   1 |  48 |                         # [Xd] Polarization function bands
%
% EnRngeXd
  0.00000 | 10.00000 |         eV    # [Xd] Energy range
%
% DmRngeXd
 0.050000 | 0.050000 |         eV    # [Xd] Damping range
%
ETStpsXd=  500                   # [Xd] Total Energy steps
% LongDrXd
 1.000000 | 0.000000 | 0.000000 |        # [Xd] [cc] Electric Field
Looking forward to your reply.
Han Gao
School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, Shandong, China

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Daniele Varsano
Posts: 2723
Joined: Tue Mar 17, 2009 2:23 pm
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Re: How to deal with the Coulomb interaction in 2D systems?

Post by Daniele Varsano » Fri Mar 12, 2021 5:06 pm

Dear Han Gao,
can you please post your report file, and also the input? Please use the attachment button to upload the entire file, you would need to rename them in an allowed format e.g. .txt

Not relater to your problem, but please note that the value you are setting for FFTGvecs is extremely low.

Best,
Daniele
Dr. Daniele Varsano
S3-CNR Institute of Nanoscience and MaX Center, Italy
MaX - Materials design at the Exascale
http://www.nano.cnr.it
http://www.max-centre.eu/

gaohan
Posts: 15
Joined: Sun Feb 07, 2021 3:56 am

Re: How to deal with the Coulomb interaction in 2D systems?

Post by gaohan » Tue Mar 16, 2021 3:45 am

Dear Daniele,
Thank you for your kind help.
I have recalculated the eels using the default value of FFTGvecs and got the eels and alpha files. In the last reply, I used a low FFTGvecs just for test.
I have attached my all input files and output files.
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Han Gao
School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, Shandong, China

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Daniele Varsano
Posts: 2723
Joined: Tue Mar 17, 2009 2:23 pm
Contact:

Re: How to deal with the Coulomb interaction in 2D systems?

Post by Daniele Varsano » Tue Mar 16, 2021 7:03 am

Dear Han Gao,
please note you are not including the coulomb cutoff interaction.
In your input the

Code: Select all

rim_cut
keyword is missing, and the

Code: Select all

%CUTBox
namelist it is not closed.

Best,
Daniele
Dr. Daniele Varsano
S3-CNR Institute of Nanoscience and MaX Center, Italy
MaX - Materials design at the Exascale
http://www.nano.cnr.it
http://www.max-centre.eu/

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