optical properties of a metalic system

Deals with issues related to computation of optical spectra in reciprocal space: RPA, TDDFT, local field effects.

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waynebeibei
Posts: 19
Joined: Fri Nov 25, 2011 2:45 pm

optical properties of a metalic system

Post by waynebeibei » Thu May 30, 2013 9:03 am

Dear all,

I am dealing with a 2d system (which is metallic using DFT and semiconducting considering GW correction).
Can I calculate optical properties using BSE for such system?

My current version is yambo-3.3.0-rev41. After GW calculation, by typing 'yambo -o b -V qp -y d', I got the error as
'[ERROR] STOP signal received while in :[07] Bethe-Salpeter Kernel
[ERROR]Fractional e/h occupations found. BS coupling forced.'

I wonder to know is there any method can be used to fix it? How about using the new version 3.4.0?

Many thanks!
Yan Jiaxu
yanjiaxu@gmail.com
School of Physical and Mathematical Sciences,
Nanyang Technological University,
Singapore 637371

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Daniele Varsano
Posts: 4198
Joined: Tue Mar 17, 2009 2:23 pm
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Re: optical properties of a metalic system

Post by Daniele Varsano » Thu May 30, 2013 9:12 am

Dear Waynebeibei,
sure you can use the 3.4, anyway it should work with the previous version too.
If you post your input/report we can try to have a look. It seems that the quasiparticle corrections are not been read correctly.

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/

waynebeibei
Posts: 19
Joined: Fri Nov 25, 2011 2:45 pm

Re: optical properties of a metalic system

Post by waynebeibei » Thu May 30, 2013 9:22 am

Sure. Pls find the attached files.

Many thanks for your reply.

Yan Jiaxu
You do not have the required permissions to view the files attached to this post.
yanjiaxu@gmail.com
School of Physical and Mathematical Sciences,
Nanyang Technological University,
Singapore 637371

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Daniele Varsano
Posts: 4198
Joined: Tue Mar 17, 2009 2:23 pm
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Re: optical properties of a metalic system

Post by Daniele Varsano » Thu May 30, 2013 2:52 pm

Dear Yan Jiaxu,
the problem here is that you still have fractional occupation number. You should need a self consistent calculation in order to fix them, but this part of the code it is not yet available. In order to avoid the error you could play with the occupation threshold (OccTresh variable). Anyway you should also activate the coupling
term of the BSE. Anyway I'm not expert on that. May be someone can give you more insight on how to solve the problem.

Cheers,
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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