a strange quesion about occupation

[njuxyh]

hi ,every here ?
i am now calculating graphene ,a two demension semi-metal ,zero gap.so i tried sigma=0 and sigma=1 to calulated dos respectively.
and i found when i use THE PARAMETE
ENCUT=500
PREC=A
EDIFF=1E-6
ISMEAR=1
SIGMA=0.0NEDOS=1001
NBANDS=8
LOPTICS=.T.
NPAR=1
LWAVE=.F.
the doscar list all the occupation is zero at all the energies.
but i lookde at the occupation in the outcar ,not that case , k-point 643 : 0.2000 0.1000 0.0000
band No. band energies occupation
1 -19.2115 2.00000
2 -8.7852 2.00000
3 -7.2001 2.00000
4 -7.1174 2.00000
5 4.1158 0.00000
6 5.5931 0.00000
7 5.8635 0.00000
8 6.9209 0.00000

k-point 644 : 0.2083 0.1000 0.0000
band No. band energies occupation
1 -19.1126 2.00000
2 -8.9891 2.00000
3 -7.2098 2.00000
4 -7.0843 2.00000
5 4.2528 0.00000
6 5.4344 0.00000
7 5.9394 0.00000
8 7.0530 0.00000

k-point 645 : 0.2167 0.1000 0.0000
band No. band energies occupation
1 -19.0106 2.00000
2 -9.1952 2.00000
3 -7.2996 2.00000
4 -6.9652 2.00000
5 4.3942 0.00000
6 5.2302 0.00000
7 6.0629 0.00000

many kpoints have the same occupation like above .
so there is a inconsistency ? i am woudering ,does the sigma=0 cause ? in my idea, the sigma is uesd to accelerate
convergence ,and here ,i use 0 also can convergence .


and a anther question maybe more fundamental how to choose the ismearing and sigma as to the zero-gap semi-metal ,like one-layer graphene?


i will appreciate if anyone would give me som hints


best regard
xu

<span class='smallblacktext'>[ Edited ]</span>

[support_vasp]

Hi,

We're sorry that we didn’t answer your question. This does not live up to the quality of support that we aim to provide. The team has since expanded. If we can still help with your problem, please ask again in a new post, linking to this one, and we will answer as quickly as possible.

Best wishes,

VASP