Problems with graphane band structure
Posted: Tue Feb 15, 2011 3:09 pm
Hello,
I have been trying to find the correct parameters to get an accurate band structure calculation of graphane (graphene with absorbed hydrogen). My parameters seemed to work with graphene, but when I calculate graphane, I find that the bands above the fermi energy don't match previously published results, and that it seems that I get the same band over and over again, just at slightly different energies. Below the fermi energy, everything seems to be correct. My parameters are:
Electronic Relaxation Run:
POSCAR:
2.13129 -1.2305 0
2.13129 1.2305 0
0.0 0.0 50.0
2 2
Cartesian
1.42086 0 0
2.84172 0 0
1.42086 0 1.10
2.84172 0 -1.10
KPOINTS
Automatic mesh
0
Gamma
11 11 1
0 0 0
INCAR
ENCUT = 500
PREC = Accurate
EDIFF = 1E-06
IALGO = 48
NELM = 40
NELMIN = 3
Ionic Relaxation Run:
KPOINTS is the same
INCAR
IBRION = 2
ISIF = 2
NSW=100
POTIM = 0.5
ENCUT = 500
PREC = Accurate
NBANDS=20
Density of States Calculation
KPOINTS
Automatic mesh
0
Gamma
33 33 1
0 0 0
INCAR
ISMEAR = -5
SIGMA = 0.12
ENCUT = 500
PREC = Accurate
NBANDS=20
Band Structure Calculation
KPOINTS
HEX
100
Line-mode
reciprocal
0.3333 -0.3333 0.000 ! K
0.000 0.000 0.000 ! \Gamma
0.000 0.000 0.000 ! \Gamma
0.500 0.000 0.000 ! M
0.500 0.000 0.000 ! M
0.3333 -0.3333 0.000 ! K
INCAR
ICHARG = 11
IBRION = -1
NSW = 0
ISMEAR = 0
SIGMA = 0.05
ENCUT = 500
PREC = Accurate
NBANDS=20
Any suggestions would be greatly appreciated. Let me know if there is any more information I can provide. I would like to show a picture of what I am talking about, but I don't know how to do that in the forum. Thanks in advance!
-Tim Hecht
I have been trying to find the correct parameters to get an accurate band structure calculation of graphane (graphene with absorbed hydrogen). My parameters seemed to work with graphene, but when I calculate graphane, I find that the bands above the fermi energy don't match previously published results, and that it seems that I get the same band over and over again, just at slightly different energies. Below the fermi energy, everything seems to be correct. My parameters are:
Electronic Relaxation Run:
POSCAR:
2.13129 -1.2305 0
2.13129 1.2305 0
0.0 0.0 50.0
2 2
Cartesian
1.42086 0 0
2.84172 0 0
1.42086 0 1.10
2.84172 0 -1.10
KPOINTS
Automatic mesh
0
Gamma
11 11 1
0 0 0
INCAR
ENCUT = 500
PREC = Accurate
EDIFF = 1E-06
IALGO = 48
NELM = 40
NELMIN = 3
Ionic Relaxation Run:
KPOINTS is the same
INCAR
IBRION = 2
ISIF = 2
NSW=100
POTIM = 0.5
ENCUT = 500
PREC = Accurate
NBANDS=20
Density of States Calculation
KPOINTS
Automatic mesh
0
Gamma
33 33 1
0 0 0
INCAR
ISMEAR = -5
SIGMA = 0.12
ENCUT = 500
PREC = Accurate
NBANDS=20
Band Structure Calculation
KPOINTS
HEX
100
Line-mode
reciprocal
0.3333 -0.3333 0.000 ! K
0.000 0.000 0.000 ! \Gamma
0.000 0.000 0.000 ! \Gamma
0.500 0.000 0.000 ! M
0.500 0.000 0.000 ! M
0.3333 -0.3333 0.000 ! K
INCAR
ICHARG = 11
IBRION = -1
NSW = 0
ISMEAR = 0
SIGMA = 0.05
ENCUT = 500
PREC = Accurate
NBANDS=20
Any suggestions would be greatly appreciated. Let me know if there is any more information I can provide. I would like to show a picture of what I am talking about, but I don't know how to do that in the forum. Thanks in advance!
-Tim Hecht