Relation between excess charge and external electric field

[santanumahapatra]

Hello,
I am using the NELECT tag to perform charged calculations of my system. However, I want to understand the relation between this excess charge and any applied external electric field. In other words, if I want to experimentally model the NELECT based simulation by applying an external bias, approximately how much bias will be required for each additional electron added to the system?

Thank you.

[michael_wolloch]

Hello santanumahapatra,

I am not sure if I understand your question. NELECT will adjust the total charge in your system. If you want to model an external electric field, I think the EFIELD tag is what you want.

If you have specific problems in your calculation setup, please follow the posting guidelines and provide the input and output files of a minimal reproducible example for your issue.

Cheers, Michael

[santanumahapatra]

Apologies if I was not very clear before, what I meant was using NELECT we are changing the total charge in the system, either increase or decrease. How do I correlated this effect in terms of external applied bias? How do I apply an external bias to add charge in the system corresponding to a particular NELECT? Is there any specific formula which can be used to relate the extra charge supplied by NELECT to an external bias?
Thanks

[michael_wolloch]

Hello Santanumahapatra,

NELECT creates a uniform background charge to the system. The total charge density is then relaxed, including this background charge.
To relate this to an experiment, you would need to charge your sample accordingly. I guess you could figure out the necessary charge based on the molar mass of the sample. How to do this exactly is a question to ask an experimentalist, I think.

Please understand that the using VASP forum is for specific questions regarding the usage of VASP, not a general physics forum. If you want, I am happy to transfer the topic to the from users for users forum for a broader discussion.

If you have a VASP-specific question on the matter of NELECT, I am of course more than happy to help you further.

All the best, Michael

[santanumahapatra]

Please transfer the topic to the from users for users forum for a broader discussion