Issue about local electric field strength calculation
Hello everyone,
I am currently working on calculating the local electric field of a system, as shown in the attached figure.
Based on Bader charge analysis and charge density difference calculations, Region I has gained electrons and carries a negative charge, while Region II has lost electrons and carries a positive charge.
Following the discussion in this post: https://ww.vasp.at/forum/viewtopic.php? ... 3e3ff95b40, I learned that the electrostatic potential recorded in VASP’s LOCPOT file is referenced to electrons.
Therefore, I used the formula E=−Δ(LOCPOT/−e)/Δz to calculate the electric field strength along the z-direction.
The results show that the average electric field strength in the yellow region between Region I and Region II is positive, meaning the electric field points along the positive z-direction.
However, this is opposite to the direction predicted by the parallel plate capacitor model, where the electric field is expected to point from the positive to the negative charge.
I would like to ask:
1. Is there any issue with my method for calculating the electric field strength?
2. What might be the reason for the discrepancy between my analysis and the parallel plate capacitor model? Is the parallel plate capacitor model applicable in this case?
Thank you very much!