Why the Dirac point of pristine monolayer graphene is above the Fermi level |
- Date: 2024/09/01 00:38
- Name: Kieran
<skn_neu@hotmail.co.uk>
- Dear All,
I am running the test calculation of the band structure for the pristine monolayer graphene with 4 by 4 by 1 supercell. This is my input file.
# File Name
System.CurrrentDirectory ./ # default=./
System.Name SLG_441
level.of.stdout 1 # default=1 (1-3)
level.of.fileout 0 # default=1 (0-2)
DATA.PATH /public21/soft/openmx/openmx3.9/DFT_DATA19/
Species.Number 1
# Definition of Atomic Species
<Definition.of.Atomic.Species
C C6.0-s3p2d2 C_PBE19
Definition.of.Atomic.Species>
# Atoms
Atoms.Number 32
Atoms.SpeciesAndCoordinates.Unit Ang # Ang|AU
<Atoms.SpeciesAndCoordinates
1 C 0.0000000000 0.0000000000 11.7000000000 2.0 2.0
2 C 1.2300000367 0.7101408633 11.7000000000 2.0 2.0
3 C -1.2300000000 2.1304225263 11.7000000000 2.0 2.0
4 C 0.0000000367 2.8405633896 11.7000000000 2.0 2.0
5 C -2.4600000000 4.2608450527 11.7000000000 2.0 2.0
6 C -1.2299999633 4.9709859160 11.7000000000 2.0 2.0
7 C -3.6900000000 6.3912675790 11.7000000000 2.0 2.0
8 C -2.4599999633 7.1014084423 11.7000000000 2.0 2.0
9 C 2.4600000000 0.0000000000 11.7000000000 2.0 2.0
10 C 3.6900000367 0.7101408633 11.7000000000 2.0 2.0
11 C 1.2300000000 2.1304225263 11.7000000000 2.0 2.0
12 C 2.4600000367 2.8405633896 11.7000000000 2.0 2.0
13 C 0.0000000000 4.2608450527 11.7000000000 2.0 2.0
14 C 1.2300000367 4.9709859160 11.7000000000 2.0 2.0
15 C -1.2300000000 6.3912675790 11.7000000000 2.0 2.0
16 C 0.0000000367 7.1014084423 11.7000000000 2.0 2.0
17 C 4.9200000000 0.0000000000 11.7000000000 2.0 2.0
18 C 6.1500000367 0.7101408633 11.7000000000 2.0 2.0
19 C 3.6900000000 2.1304225263 11.7000000000 2.0 2.0
20 C 4.9200000367 2.8405633896 11.7000000000 2.0 2.0
21 C 2.4600000000 4.2608450527 11.7000000000 2.0 2.0
22 C 3.6900000367 4.9709859160 11.7000000000 2.0 2.0
23 C 1.2300000000 6.3912675790 11.7000000000 2.0 2.0
24 C 2.4600000367 7.1014084423 11.7000000000 2.0 2.0
25 C 7.3800000000 0.0000000000 11.7000000000 2.0 2.0
26 C 8.6100000367 0.7101408633 11.7000000000 2.0 2.0
27 C 6.1500000000 2.1304225263 11.7000000000 2.0 2.0
28 C 7.3800000367 2.8405633896 11.7000000000 2.0 2.0
29 C 4.9200000000 4.2608450527 11.7000000000 2.0 2.0
30 C 6.1500000367 4.9709859160 11.7000000000 2.0 2.0
31 C 3.6900000000 6.3912675790 11.7000000000 2.0 2.0
32 C 4.9200000367 7.1014084423 11.7000000000 2.0 2.0
Atoms.SpeciesAndCoordinates>
Atoms.UnitVectors.Unit Ang # Ang|AU
<Atoms.UnitVectors
9.8400000000 0.0000000000 0.0000000000
-4.9200000000 8.5216901054 0.0000000000
0.0000000000 0.0000000000 23.4000000000
Atoms.UnitVectors>
# SCF or Electronic System
scf.XcType LDA # LDA|LSDA-CA|LSDA-PW|GGA-PBE
scf.SpinPolarization off # On|Off|NC
scf.ElectronicTemperature 600.0 # default=300 (K)
scf.energycutoff 350.0 # default=150 (Ry)
scf.maxIter 100 # default=40
scf.EigenvalueSolver Band # DC|GDC|Cluster|Band
scf.lapack.dste dstevx # dstegr|dstedc|dstevx, default=dstegr
scf.Kgrid 100 1 1 # means n1 x n2 x n3
scf.Mixing.Type rmm-diisk # Simple|Rmm-Diis|Gr-Pulay|Kerker|Rmm-Diisk
scf.Init.Mixing.Weight 0.010 # default=0.30
scf.Min.Mixing.Weight 0.001 # default=0.001
scf.Max.Mixing.Weight 0.020 # default=0.40
scf.Mixing.History 20 # default=5
scf.Mixing.StartPulay 7 # default=6
scf.criterion 1.0e-10 # default=1.0e-6 (Hartree)
# MD or Geometry Optimization
MD.Type Nomd # Opt|EF|BFGS|RF|DIIS
MD.Opt.DIIS.History 6 # default=3
MD.Opt.StartDIIS 7 # default=5
MD.Opt.EveryDIIS 6 # default=10
MD.maxIter 100 #
MD.Opt.criterion 1.0e-4 # default=1.0e-4 (a.u.)
<MD.Fixed.XYZ
1 1 1 1
2 1 1 1
3 1 1 1
4 1 1 1
5 1 1 1
6 1 1 1
7 1 1 1
8 1 1 1
9 1 1 1
10 1 1 1
11 1 1 1
12 1 1 1
13 1 1 1
14 1 1 1
15 1 1 1
16 1 1 1
17 1 1 1
18 1 1 1
19 1 1 1
20 1 1 1
21 1 1 1
22 1 1 1
23 1 1 1
24 1 1 1
25 1 1 1
26 1 1 1
27 1 1 1
28 1 1 1
29 1 1 1
30 1 1 1
31 1 1 1
32 1 1 1
MD.Fixed.XYZ>
# Band dispersion
Band.dispersion on # on|off, default=off
Band.Nkpath 2
<Band.kpath
100 0.0 0.0 0.0 0.3333333333 0.3333333333 0.0 G K
100 0.3333333333 0.3333333333 0.0 0.5 0.0 0.0 K M
Band.kpath>
# DOS and PDOS
Dos.fileout off # on|off, default=off
Dos.Erange -15.0 25.0 # default = -20 20
Dos.Kgrid 600 1 1 # default = Kgrid1 Kgrid2 Kgrid3
DosGauss.fileout off
DosGauss.Num.Mesh 4000
DosGauss.Width 0.01
After the calculation, I extracted the band structure and found that the Dirac point of the monolayer graphene is 0.035 eV above the Fermi energy level. The dirac point actually should be located at Fermi energy level.
Is this problem from the pseudopotential or something else? Would anyone please give me some suggestions/comments, according to my input file?
Thank you in advance.
Kieran
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