Wannier band strcuture is incosinstent

[nicholas_dimakis1]

Hello

I am using VASP 6.5.0 to generate the band structure for the MoS2 monolayer. The INCAR file is given below

Code: Select all

SYSTEM  = MoS2

#NCORE  = 4
KPAR   = 2

ENCUT   = 500
IBRION  = -1

ISMEAR  = 0
SIGMA   = 0.01
NBANDS  = 96
NEDOS   = 3000

PREC    = Accurate
EDIFF   = 1.e-8
LREAL   = False
LASPH   = True
NELMIN = 10
LWANNIER90_RUN = True
NUM_WANN = 96
WANNIER90_WIN = "
Begin projections
Random
End projections
guiding_centres = .true

# plot bands
bands_plot = true

begin kpoint_path      

   GAMMA  0.00000000  0.00000000  0.00000000        M  0.50000000  0.00000000  0.00000000
       M  0.50000000  0.00000000  0.00000000        K  0.33333333  0.33333333  0.00000000
       K  0.33333333  0.33333333  0.00000000    GAMMA  0.00000000  0.00000000  0.00000000
end kpoint_path
"

The wannier band structure produced is very different from the one vasp produces using

Code: Select all

login1.ls6(1367)$ more INCAR 
SYSTEM  = MoTe2

#NCORE  = 4
KPAR   = 2

ENCUT   = 500
IBRION  = 2

ICHARG = 11
LWAVE = .TRUE.
LCHARG = .TRUE.
LVTOT = .FALSE.
LVHAR = .FALSE.
LELF = .FALSE.
LORBIT = 11
NEDOS = 1000

ISMEAR  = 0
SIGMA   = 0.05
NBANDS  = 65
#NEDOS   = 3000

PREC    = Accurate
EDIFF   = 1.e-5
LREAL   = False
LASPH   = True

and

Code: Select all

login1.ls6(1368)$ more KPOINTS 
K-Path Generated by VASPKIT.
   20
Line-Mode
Reciprocal
   0.0000000000   0.0000000000   0.0000000000     GAMMA          

   0.5000000000   0.0000000000   0.0000000000     M              
 
   0.5000000000   0.0000000000   0.0000000000     M              

   0.3333333333   0.3333333333   0.0000000000     K              
 
   0.3333333333   0.3333333333   0.0000000000     K              

   0.0000000000   0.0000000000   0.0000000000     GAMMA

I am attaching the files needed to reproduce the Wannier band structure.

Thanks-Nick

[manuel_engel1]

Dear Nick,

Thanks for reaching out. I have tried to reproduce your example, but for me everything looks OK. I have attached an image of the produced Wannier fit compared to the bandstructure obtained in VASP.

bands.png

I have produced this data using the KPOINTS_OPT and KPOINTS_WAN files, which can be done in a single VASP calculation. Otherwise, I have not changed anything about your INPUT files.

Maybe there is a problem with how you extract or plot the data?

[nicholas_dimakis1]

Thank you for your email. I have added the KPOINTS_OPT file as

login1.ls6(1115)$ more KPOINTS_OPT
K-Path Generated by VASPKIT.
20
Line-Mode
Reciprocal
0.0000000000 0.0000000000 0.0000000000 GAMMA
0.5000000000 0.0000000000 0.0000000000 M

0.5000000000 0.0000000000 0.0000000000 M
0.3333333333 0.3333333333 0.0000000000 K

0.3333333333 0.3333333333 0.0000000000 K
0.0000000000 0.0000000000 0.0000000000 GAMMA

Unfortunately, I am not getting your band structure. I am attaching the wannier input and output files and the data files from the wannier bands calculations.

Thanks-Nick

[nicholas_dimakis1]

Forgot to attach the correct files.

[manuel_engel1]

Your Wannier fit looks the same as mine, just a bit more zoomed in. Am I correct in assuming that your VASP band structure looks different then? Or do you have trouble in obtaining the VASP band structure from the output?

[nicholas_dimakis1]

Hello

Please see attached that shows the band structure for MoS2 using VASP (green lines) vs Wannier (purple lines). They are clearly very different. Not sure, why using the same file input files we get different results. I have also tried other vasp.6 versions and still the same problem persists.

Thanks-Nick

[manuel_engel1]

What you are seeing is just a shift of the energies. The two band structures look the same if one is shifted toward the other. I think what is happening is that in one case you plot relative to the Fermi level while in the other case you just plot the absolute values of the Kohn-Sham eigenvalues as they come out of the calculation.

[nicholas_dimakis1]

Thank you for your help. You are correct. They are shifted relatively to the Fermi energy.