# The gap was open when I was doing an HSE + SOC DFT calculation

I used VASP as my DFT software to do a calculation on an anti-perovskite crystal. I try to reproduce the band structure from literature which was calculated based on HSE + SOC calculation. Their result was shown below:

]2

10.1103/PhysRevB.90.081112

I try to redo the calculation and plot the band along the same high symmetry line, here is what I got ( My K-point mesh is a bit low, so it may not be so smooth) :

It seems that the two graphs are qualitatively the same. But the gap at Gamma point was open up. I have no idea what kind of mistake I've made. And here is my INCAR setting in my calculation:

 #Calculation Parameter

ISMEAR = 0 ; SIGMA = 0.05
PREC = Normal
ENCUT = 350
ISPIN = 2
LWAVE = .TRUE.
LCHARG = .TRUE.
LSORBIT = .TRUE.
MAGMOM = 15*0
SAXIS = 0 0 1
GGA_COMPAT = .FALSE.

#Electronic Relaxation

EDIFF = 1E-05
ALGO = Normal
NELM = 500

#Ionic Relaxation

IBRION = -1
NSW = 0

#HSE06

LHFCALC = .TRUE.
HFSCREEN = 0.2
ALGO = Damped
TIME = 0.4
#AEXX = 0.25

• You should give the link to the reference paper. – Jack Dec 16 '20 at 4:31
• I’ve already added the reference ! Thanks for your reminder – JensenPang Dec 16 '20 at 5:12
• You are not using the same parameters. – Jack Dec 16 '20 at 5:26
• I gave you +1 long ago, but does there need to be so much space between each line in what is now the code block? – Nike Dattani Feb 28 at 5:08
• @Jack it would probably be enough for an answer just to point out what parameters don't match the paper. – Tyberius Apr 25 at 1:24