Narrow gap materials is reported to be metallic system by yambo

Run-time issues concerning Yambo that are not covered in the above forums.

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liuyang_phy
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Joined: Tue Oct 18, 2022 3:43 am

Narrow gap materials is reported to be metallic system by yambo

Post by liuyang_phy » Tue Nov 01, 2022 3:32 am

Dear developer,

I am trying to do G0W0 calculation for a narrow gap system(around 30 meV calculated by QE) by Yambo. But, when i initialize the database by typing yambo, i found the message below:

[X] === Gaps and Widths ===
[X] Conduction Band Min : -0.950537 [eV]
[X] Valence Band Max : -0.950537 [eV]
[X] Filled Bands : 15
[X] Metallic Bands : 16 17
[X] Empty Bands : 18 420
If i continue to do the GW calculation, there will be an WARNING message ([WARNING] The system is a metal but Drude term not included) in the repore file. Why yambo report a narrow gap system to be metallic ?
How should i deal with this narrow gap system in yambo? Should i include the Drude term and how to include it?

Thank you so much!

Liu Yang
PhD student
Hua zhong university of science and technology, China

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Daniele Varsano
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Re: Narrow gap materials is reported to be metallic system by yambo

Post by Daniele Varsano » Wed Nov 02, 2022 4:26 pm

Dear Liu,

you can try to remove all the ndb* file in the SAVE directory and repeat the setup setting:

Code: Select all

setup
ElecTemp= 0.0 eV 
and see it this solve the problem.

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/

liuyang_phy
Posts: 6
Joined: Tue Oct 18, 2022 3:43 am

Re: Narrow gap materials is reported to be metallic system by yambo

Post by liuyang_phy » Sun Nov 06, 2022 10:19 am

Daniele Varsano wrote: Wed Nov 02, 2022 4:26 pm Dear Liu,

you can try to remove all the ndb* file in the SAVE directory and repeat the setup setting:

Code: Select all

setup
ElecTemp= 0.0 eV 
and see it this solve the problem.

Best,
Daniele
Thank you very much. It seems works normally when i just follow your instructions. But why the default initialization set the electronic temperature to be 0.025861 eV(300K) ?
Best wishes
Liu Yang

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Daniele Varsano
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Re: Narrow gap materials is reported to be metallic system by yambo

Post by Daniele Varsano » Mon Nov 07, 2022 8:14 am

Dear Liu,
most probably because you used a smearing in the QE ground state calculation and Yambo and QE use a different smearing 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/

liuyang_phy
Posts: 6
Joined: Tue Oct 18, 2022 3:43 am

Re: Narrow gap materials is reported to be metallic system by yambo

Post by liuyang_phy » Mon Nov 14, 2022 8:38 am

Daniele Varsano wrote: Mon Nov 07, 2022 8:14 am Dear Liu,
most probably because you used a smearing in the QE ground state calculation and Yambo and QE use a different smearing function.
Best,
Daniele
Dear Daniele,
Does it means that i should set "ElecTemp= 0.0 eV" in each of my input file (such as G0W0 or BSE calculation) if i used a smearing in the QE ground calculation? looking forward to hearing from you and thank you very much!
Yours sincerely,
Liu Yang

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Daniele Varsano
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Re: Narrow gap materials is reported to be metallic system by yambo

Post by Daniele Varsano » Tue Nov 15, 2022 11:26 am

Dear Liu Yang,
yes, you should keep it in your calculations.

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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