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Electric field calculations
Posted: Wed Jul 20, 2022 2:32 pm
by karthik_hj
I gave the electric field to an already relaxed structure and it shows 'electronic self consistency is not achieved'. I even tried NELM=300 but still the ground state energy has not been converged. If I put ISIF 2 tag along with electric field tag, calculations ends abruptly showing error. Is there anything else we can do. Would it be right if I take the CONTCAR after giving electric field and relax it again using ISIF tags?
Or is there another procedure to do the same
I put idipol ldipol and electric field tags in the INCAR . Should I put dipol tag and Efield_pead tag also
I want to find the effect of electric field on the electronic structure of a 2d metallic system
Re: Electric field calculations
Posted: Wed Jul 20, 2022 10:05 pm
by henrique_miranda
What is the error that you obtain when you say that the calculation ends abruptly?
Could you share the INCAR, POSCAR, KPOINTS, POTCAR and OUTCAR files?
Re: Electric field calculations
Posted: Fri Jul 22, 2022 1:50 pm
by karthik_hj
The error is gone now when i put dipol tag also along with isif-2. Is it the correct procedure? What does an efield_pead tag do ? Could you provide a workflow for the electric field calculations for a structure?
Re: Electric field calculations
Posted: Fri Jul 22, 2022 3:42 pm
by henrique_miranda
The error is gone now when i put dipol tag also along with isif-2. Is it the correct procedure?
I don't know why setting ISIF would have any influence on the self-consistent computation with an electric field.
What does an efield_pead tag do ?
It applies an electric field.
wiki/index.php/EFIELD_PEAD
Could you provide a workflow for the electric field calculations for a structure
I don't understand what you mean
Re: Electric field calculations
Posted: Wed Jul 27, 2022 5:51 am
by karthik_hj
I gave electric field using
LDIPOL = .TRUE.
EFIELD = 1.0
IDIPOL = 3
DIPOL = 0.5 0.5 0.5
Is it necessary to give EFIELD_PEAD tag? What does it do?
What i mean by workflow is the procedure to do electric field calculations. Please see whether which workflow is correct
Workflow 1
Give Electric field tags in INCAR and relax the structure with NSW=0
Give Electric field tags in INCAR and find dos and similarly bandstructure NSW=0
Workflow 2
Give Electric field tags in INCAR and relax the structure with NSW=0
Do not give Electric field tags in INCAR to find dos and bandstructure
Re: Electric field calculations
Posted: Thu Jul 28, 2022 3:54 pm
by henrique_miranda
The EFIELD tag refers to the electric field applied using the method described in
https://doi.org/10.1103/PhysRevB.46.16067
This works for slabs or molecules as mentioned on this page:
wiki/index.php/Monopole_Dipole_and_Quad ... orrections
The EFIELD_PEAD tag refers to the electric field applied using the method described in
https://doi.org/10.1103/PhysRevB.63.155107
This also works for bulk systems and its described on this page:
wiki/index.php/Berry_phases_and_finite_ ... ric_fields
You should not mix these two INCAR tags.
Workflow 1 is the correct one.
Re: Electric field calculations
Posted: Mon Aug 01, 2022 5:03 am
by karthik_hj
Can these methods be only used for insulators/semiconductors? Because when I used EFIELD_PEAD for metals ,VASP exited.
Re: Electric field calculations
Posted: Mon Aug 01, 2022 5:12 am
by henrique_miranda
EFIELD_PEAD only works for systems with a gap:
https://www.vasp.at/wiki/index.php/EFIELD_PEAD
The maximum magnitude of the electric field you can apply is limited by the size of the gap of the system.