[Pw_forum] Comments on Graphene on BN relaxation
mohamed sabri majdoub
majdoub at gmail.com
Tue Jan 26 17:22:20 CET 2010
Dear all,
I run calculations of 1 layer of graphene on bilyaer boron nitride.
I am trying to study the Energy vs cutoff and Energy vs interlayer distance
d between the graphene layer and top of BN layer.
I got the following results after several runs. Is it the right way to do
it?
Here is the input file I am using:
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
&control
title = 'GphBN'
calculation = 'relax'
outdir = '/pwscf/pwscftemp'
prefix = 'GphBN'
pseudo_dir = '/pseudopot-C-B-N'
tprnfor = .t.
restart_mode = 'from_scratch'
wf_collect = .true.
disk_io = 'low'
/
&system
ibrav = 0,
celldm(1) = 1.8897261
nat = 72,
ntyp = 3,
ecutwfc = 60.0
occupations = 'smearing'
smearing = 'gaussian'
degauss = 0.003675
/
&electrons
mixing_mode = 'local-TF'
mixing_beta = 0.05
diagonalization = 'david'
conv_thr = 1.D-5
/
&ions
trust_radius_ini = 0.10
/
&cell
ATOMIC_SPECIES
B 10.81100 B.pz-vbc.UPF
C 12.01070 C.pz-vbc.UPF
N 14.00674 N.pz-vbc.UPF
ATOMIC_POSITIONS angstrom
B 0.710000 8.607000 11.306000
B 0.710000 11.066000 11.306000
B 2.840000 7.377000 11.306000
B 0.710000 6.148000 11.306000
B 6.390000 6.148000 8.000000
B 6.390000 8.607000 8.000000
B 6.390000 11.066000 8.000000
B 2.840000 9.836000 11.306000
B 7.100000 7.377000 11.306000
B 7.100000 9.836000 11.306000
B 7.100000 12.295000 11.306000
B 4.970000 11.066000 11.306000
B 2.840000 12.295000 11.306000
B 4.970000 6.148000 11.306000
B 4.970000 8.607000 11.306000
B 4.260000 7.377000 8.000000
B 2.130000 11.066000 8.000000
B 2.130000 8.607000 8.000000
B 2.130000 6.148000 8.000000
B 4.260000 9.836000 8.000000
B 0.000000 7.377000 8.000000
B 0.000000 9.836000 8.000000
B 4.260000 12.295000 8.000000
B 0.000000 12.295000 8.000000
C 2.130000 6.148000 14.106000
C 2.130000 8.607000 14.106000
C 2.130000 11.066000 14.106000
C 0.000000 12.295000 14.106000
C 0.000000 9.836000 14.106000
C 0.000000 7.377000 14.106000
C 0.710000 11.066000 14.106000
C 0.710000 8.607000 14.106000
C 0.710000 6.148000 14.106000
C 6.390000 8.607000 14.106000
C 6.390000 6.148000 14.106000
C 4.970000 11.066000 14.106000
C 6.390000 11.066000 14.106000
C 7.100000 12.295000 14.106000
C 7.100000 9.836000 14.106000
C 7.100000 7.377000 14.106000
C 4.970000 8.607000 14.106000
C 2.840000 12.295000 14.106000
C 2.840000 9.836000 14.106000
C 2.840000 7.377000 14.106000
C 4.260000 7.377000 14.106000
C 4.970000 6.148000 14.106000
C 4.260000 12.295000 14.106000
C 4.260000 9.836000 14.106000
N 0.000000 12.295000 11.306000
N 0.000000 9.836000 11.306000
N 0.000000 7.377000 11.306000
N 2.840000 7.377000 8.000000
N 2.840000 9.836000 8.000000
N 2.840000 12.295000 8.000000
N 4.970000 11.066000 8.000000
N 4.970000 8.607000 8.000000
N 4.970000 6.148000 8.000000
N 7.100000 12.295000 8.000000
N 7.100000 9.836000 8.000000
N 7.100000 7.377000 8.000000
N 0.710000 6.148000 8.000000
N 0.710000 8.607000 8.000000
N 0.710000 11.066000 8.000000
N 6.390000 11.066000 11.306000
N 6.390000 8.607000 11.306000
N 6.390000 6.148000 11.306000
N 2.130000 11.066000 11.306000
N 2.130000 8.607000 11.306000
N 2.130000 6.148000 11.306000
N 4.260000 12.295000 11.306000
N 4.260000 9.836000 11.306000
N 4.260000 7.377000 11.306000
K_POINTS automatic
10 10 1 1 1 0
CELL_PARAMETERS
8.51980 0.00000 0.00000
0.00000 7.37600 0.00000
0.00000 0.00000 22.6120
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------
The results are :
1- Final energy (obtained from last relaxation step) vs cutoff (ecutwfc)
cut20: Final energy = -857.6291985882 Ry
cut30: Final energy = -876.5012327526 Ry
cut40: Final energy = -885.4765196610 Ry
cut50: Final energy = -890.0493283821 Ry
cut60: Final energy = -892.0114549785 Ry
cut70: Final energy = -892.8706506804 Ry
cut80: Final energy = -893.2520149989 Ry
When I plot the graph, it looks like ecutwfc =60 is optimal. Is it right? Is
it the right way to do it? Is the final energy (obtained from last
relaxation step) the right quantity?
------------------------------------------------------------------------------------------------------------------------------------------------------------
2- For Final energy (obtained from last relaxation step) vs d interlayer
distance at cutoff ecutwfc = 60.0:
d=2.5= Final energy = -892.0122348924 Ry
d=3.0= Final energy = -892.0119194861 Ry
d=3.1= Final energy = -892.0089055437 Ry
d=3.2= Final energy = -892.0104083862 Ry
d=3.3= Final energy = -892.0115677649 Ry
d=3.4= Final energy = -892.0113018510 Ry
d=3.5= Final energy = -892.0121118001 Ry
d=3.6= Final energy = -892.0113544429 Ry
d=3.7= Final energy = -892.0096184164 Ry
d=3.9= Final energy = -892.0041914533 Ry
There are fluctuations in the data? Is it normal?
-----------------------------------------------------------------------------------------------------------------------------------------------------
3- For Final energy (obtained from last relaxation step) vs d interlayer
distance at cutoff ecutwfc = 50.0:
d=2.5= Final energy = -890.0504214490 Ry
d=2.8= Final energy = -890.0503533642 Ry
d=2.9= Final energy = -890.0503471460 Ry
d=3.0= Final energy = -890.0486572147 Ry
d=3.1= Final energy = -890.0491375298 Ry
d=3.2= Final energy = -890.0480863744 Ry
d=3.3= Final energy = -890.0492074574 Ry
d=3.4= Final energy = -890.0501303488 Ry
d=3.6= Final energy = -890.0488317041 Ry
d=3.5= Final energy = -890.0492797825 Ry
d=3.7= Final energy = -890.0470527582 Ry
d=3.8= Final energy = -890.0443250729 Ry
d=3.9= Final energy = -890.0412177248 Ry
Same thing for these data.
Is there any thing wrong?
Your suggestions are welcomed.
Thank you in advance for your help!
Regards,
ME
University of Houston
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