Dear Wien2k developers??
When YS-PBE0 is used to calculate the DOS of pristine h-BN, the problem I
encounter is that I don't know how to select the appropriate nband to obtain
the DOS of energy window -20 eV ~ 20 eV.
At first, I calculated the DOS of pristine h-BN using PBE96. The emin and emax
in case.in1 file are -9.0 and 2.5, respectively. I can easily get the DOS of
-20 eV ~ 20 eV that I need. Then I executed init_hf_lapw, and I set nband in
case.inhf file to 14 ( the number of occupied bands plus one) according to the
following contents in case.scf
:BAN00001: 1 -1.024214 -0.744172
2.00000000
:BAN00002: 2 -1.013037 -0.743874
2.00000000
:BAN00003: 3 -0.370466 -0.032709
2.00000000
:BAN00004: 4 -0.368369 0.033611
2.00000000
:BAN00005: 5 -0.240838 0.187128
2.00000000
:BAN00006: 6 -0.240784 0.187128
2.00000000
:BAN00007: 7 -0.006555 0.283584
2.00000000
:BAN00008: 8 0.032524 0.287635
2.00000000
:BAN00009: 9 0.598642 0.890756
0.00000000
:BAN00010: 10 0.625260 1.041091 0.00000000
:BAN00011: 11 0.874243 1.203608 0.00000000
:BAN00012: 12 1.014159 1.265192 0.00000000
:BAN00013: 13 1.122810 1.303539 0.00000000
Energy to separate low and high energystates:
-0.42047
:NOE : NUMBER OF ELECTRONS =
16.000
:FER : F E R M I - ENERGY(TETRAH.M.)= 0.2876346466
:GMA : POTENTIAL AND CHARGE CUT-OFF 12.00 Ry**.5
Meanwhile, other contents of the case.inhf file are set to YS-PBE0 for
calculation. When I executed run_lapw -hf and finished the DOS calculation, I
found that the energy window maximum of DOS can only reach 13.42366 eV,
but emin and emax in the case.in1 file are still -9.0 and 2.5. I noticed that
first three lines of case.dos1ev in PBE96 calculations show:
# BAND 28
#EF= 0.00000 NDOS= 3 NENRG=
1750 Gaussian bradening: 0.01600
# ENERGY total-DOS 1:total
2:total
Therefore, I changed the nband of case.inhf file in YS-PBE0 calculation to 28,
and finally successfully calculated the density of States of -20 eV ~ 20 eV
that I needed. Because the structure of h-BN is very simple, when I increase
nband from 14 to 28, the increase of calculation time is not particularly
obvious.
When I need to calculate the DOS of h-BN with defects, I set 3*3*1
supercell. At this time, nband obtained from case.scf and nband obtained
from case.dos1ev are 79 and 910, respectively. I guess that when 79 is used,
the complete density of States of -20 eV ~ 20 eV cannot be obtained, and when
910 is used, the calculation time cannot be tolerated. Is there a better
solution to this situation?
Any comments would be highly appreciated. Thanks in advance!
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