How to describe the effect of electric field on interlayer distcance

[yuc111]

Hi, all!

I would like to use VASP to calculate the interlayer distance with the effect of external electric field in bilayer BN. in this regard, I need to relax the lattice by using EFIELD or EFIELD_PEAD block in INCAR, but I get the different trend compared with experiments. So I am wondering is there any correct approaches, which can correctly describe the enfluence of the real electric field force? for example AIMD calculation under the elctric field?

Thank you for your time!

Regards,
Aster

[alexey.tal]

Dear Aster,

I moved your post to the "From users for users" section of our forum, since it is more of a question for the user community. Perhaps someone familiar with this problem can share their experience.
I don't have expertise in this topic, but it seems to me that it should be a relaxation calculation in the presence of an electric field, so I don't see why running AIMD would be a better way to relax the structure under the electric field. On the other hand, if the temperature effects play a major role for this system, AIMD would be a way to include the atomic vibrations.
If you provide more information, i.e., input and output files I can check if I see something that appears wrong in the way you set up your calculation.
Here are some things that one should be generally aware of for this type of calculations:

• Considering that it is a bilayer BN, one would need to include Van der Waals corrections to reproduce the experimental interlayer distance.
• One would likely need to include the dipole corrections for such a calculation.
• It is necessary to include a substantial amount of vacuum to avoid spurious interaction between periodic images.

Best wishes,
Alexey

[yuc111]

Thank you for your quich response, In fact, I didn't run wrongly. I just have the difference trend of field vs. distance compared with the experiment. So, I suspect my input file for relaxing the structure under electric field does not accurately reflect the forces the structure acctually fells, so I post this topic for more help. For your convinence, I put the attchment of INCAR for your review. Looking forward to you!

ISTART = 1 (Read existing wavefunction, if there)
ISPIN = 1 (Non-Spin polarised DFT)
LATTICE_CONSTRAINTS = .TRUE. .TRUE. .FALSE.
LREAL = .FALSE. (Projection operators: automatic)
ENCUT = 500 (Cut-off energy for plane wave basis set, in eV)
PREC = A (Precision level: Normal or Accurate, set Accurate when perform structure lattice relaxation calculation)
LWAVE = .F. (Write WAVECAR or not)
LCHARG = .F. (Write CHGCAR or not)
ADDGRID= .TRUE. (Increase grid, helps GGA convergence)
#LASPH = .TRUE. (Give more accurate total energies and band structure calculations)
#PREC = Accurate (Accurate strictly avoids any aliasing or wrap around errors)
#SYMPREC = 1E-05
#Electronic Relaxation
ISMEAR = 0 (Gaussian smearing, metals:1)
SIGMA = 0.05 (Smearing value in eV, metals:0.2)
NELM = 150 (Max electronic SCF steps)
NELMIN = 6 (Min electronic SCF steps)
EDIFF = 1E-06 (SCF energy convergence, in eV)
# GGA = PS (PBEsol exchange-correlation)
NPAR = 4
#Ionic Relaxation
IALGO = 38
NSW = 200 (Max ionic steps)
IBRION = 3 (Algorithm: 0-MD, 1-Quasi-New, 2-CG)
ISIF = 3 (Stress/relaxation: 2-Ions, 3-Shape/Ions/V, 4-Shape/Ions)
EDIFFG = -1E-02 (Ionic convergence, eV/AA)
ISYM = 0 (Symmetry: 0=none, 2=GGA, 3=hybrids)
IVDW = 11
#DIPOL
IDIPOL = 3
LDIPOL = .TRUE.
DIPOL = 0.5 0.5 0.5
EFIELD = 0 0 0.02

2. another method
#Global Parameters
ISTART = 1 (Read existing wavefunction, if there)
ISPIN = 1 (Non-Spin polarised DFT)
LATTICE_CONSTRAINTS = .TRUE. .TRUE. .FALSE.
LREAL = .FALSE. (Projection operators: automatic)
ENCUT = 520 (Cut-off energy for plane wave basis set, in eV)
PREC = A (Precision level: Normal or Accurate, set Accurate when perform structure lattice relaxation calculation)
LWAVE = .F. (Write WAVECAR or not)
LCHARG = .F. (Write CHGCAR or not)
#ADDGRID= .TRUE. (Increase grid, helps GGA convergence)
#LASPH = .TRUE. (Give more accurate total energies and band structure calculations)
#PREC = Accurate (Accurate strictly avoids any aliasing or wrap around errors)
SYMPREC = 1E-04
#Electronic Relaxation
ISMEAR = 0 (Gaussian smearing, metals:1)
SIGMA = 0.01 (Smearing value in eV, metals:0.2)
NELM = 150 (Max electronic SCF steps)
NELMIN = 6 (Min electronic SCF steps)
EDIFFG = 1E-05 (SCF energy convergence, in eV)
# GGA = PS (PBEsol exchange-correlation)
#NPAR = 4
#Ionic Relaxation
#ALGO=A
IALGO = 38
NSW = 200 (Max ionic steps)
IBRION = 2 (Algorithm: 0-MD, 1-Quasi-New, 2-CG)
ISIF = 3 (Stress/relaxation: 2-Ions, 3-Shape/Ions/V, 4-Shape/Ions)
EDIFFG = -1E-02 (Ionic convergence, eV/AA)
ISYM = 0 (Symmetry: 0=none, 2=GGA, 3=hybrids)
LUSE_VDW = .FALSE.
IVDW = 10
#DIPOL
IDIPOL = 3
LDIPOL = .TRUE.
DIPOL = 0.5 0.5 0.5
#ELECTRIC_FIELD
LPEAD_RELAX = .TRUE.
#LCALCEPS = .TRUE.
ELECTRIC_FIELD = 0.02