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