What is the source of error in this mBJ-LDA calculation?

Question

I am trying to do MBJLDA calculation for bandstructure for WS2 monolayer unit cell using VASP and following the method provided here : Band Structure mBJ-LDA using Vasp, but I am getting an error message. The INPUTS are below:

INCAR:

ENCUT=600
PREC = Accurate
EDIFF=1E-6
NELM=300
ISMEAR=-5

###MBJ:
METAGGA=MBJ
LASPH=.TRUE.
LMAXMIX=4
GGA=CA

LDA POTCAR:

  PAW W_pv 06Nov2007                     
   TITEL  = PAW W_pv 06Nov2007
  PAW S 27Mar2009                        
   TITEL  = PAW S 27Mar2009

POSCAR:

 W2S4                                   
   1.00000000000000     
     3.1912863255000001    0.0000000000000000    0.0000000000000000
    -1.5956425563000001    2.7637348281000000    0.0000000000000000
     0.0000000000000000    0.0000000000000000   20.1269199999999984
   W    S 
     1     2
Direct
  0.6666670084824631  0.3333329922369330  0.5000000000000000
  0.3333330949386806  0.6666670699615054  0.4218851941843354
  0.3333330949386806  0.6666670699615054  0.5781148058156645
 
  0.00000000E+00  0.00000000E+00  0.00000000E+00
  0.00000000E+00  0.00000000E+00  0.00000000E+00
  0.00000000E+00  0.00000000E+00  0.00000000E+00

The calculations was based on SCF-PBE WAVECAR.

Answer 1

I assume that:

• You really care about is how to calculate the MBJ band structure of monolayer WS2.
• You can follow the linked answer: mBJ-LDA band structure calculation using VASP

For monolayer, it is very hard/tricky to converge at MBJ self-consistent calculation. Usually, one possible way is you can obtain the CMBJ=XXX from its bulk counterpart.

I have tried this but get unsatisfactory result:

• Bulk WS2 (SOC is ignored!):

  • PBE band:

  • MBJ band:

    grep CMBJ OUTCAR ====> CMBJ=1.2327
    

• Monolayer WS2:

  • PBE result:

  • MBJ result:

    INCAR

     ### Read PBE wavefunction
     ISTART=1
     ICHARG=0
     ENCUT=400
     EDIFF=1E-6
     NELM=300
     ISMEAR=-5
    
     ###MBJ:
     METAGGA=MBJ
     LASPH=.TRUE.
     LMAXMIX=4
     GGA=CA
     CMBJ=1.2327
    

This unsatisfactory result may be related to the badly converged MBJ self-consistent calculation. Unfortunately, I haven't found any solutions for this (still trying...).

By the way, the system contains only three atoms, why not using the HSE06 method?

Hope it helps.