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Thanks for your attention.

I want to calculate a slab with external electric field. For small external electric field like 0.1 ev/A, I can achieve a converged total energy with the expense of more than 80 electonic steps. unfortunately, as soon as I increase the external field to 0.5 ev/A, the calculation shows no sign of convergence and its total energy is weird, like below,
RMM: 37 -0.352981988366E+06 0.80317E+03 -0.30545E+05 9483 0.148E+04 0.258E+02
RMM: 38 -0.341332444180E+06 0.11650E+05 -0.12314E+05 9272 0.148E+04 0.253E+02
RMM: 39 -0.328795963487E+06 0.12536E+05 -0.16718E+05 9301 0.147E+04 0.252E+02
RMM: 40 -0.353055503244E+06 -0.24260E+05 -0.28073E+05 9302 0.156E+04 0.256E+02

I did lots of trial calculations. as suggested by admin or others, but shows no improvement of electronic convergence. something imappropriate with my system?
Could anyone give me a suggestion on how to handle this problem? any advices are extremely welcome!

Thanks very much!

did you switch on the dipole corrections?

Thanks admin for response!
I added three commands to the normal INCAR, see the following:

ENCUT=350.000 #cutoff
EDIFF=1.0e-05
ISIF=0
ISMEAR= 0 #BZ integration method (for relaxation runs)
LWAVE=.FALSE.
LCHARG =.FALSE.
LBERRY = .FALSE.
ISYM= 0
ALGO = Fast
LREAL= Auto
EFIELD= 0.5
IDIPOL= 3
LDIPOL= .TRUE.
NELM= 200
LMAXMIX = 6

Since LDIPOL was set to True, I think maybe the dipole correction was switched on.
Maybe I am wrong, could you please check the INCAR for me. Thanks very much for your attention!

[quote="admin"]did you switch on the dipole corrections?[/quote]
dear admin, I really want to if it is necessary to set ISYM=0 when set EFIELD=non-zero. this problem puzzle me for half a year, and I have search this problem for many times. thank you!