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DOS calculation of NiO using LDA (without PAW)
Posted: Fri Oct 21, 2011 5:21 pm
by lamsalc
Hi everybody
I am a new user of Abinit and I am trying to get DOS for NiO. I added following lines
prtdos 3 natsph 4 iatsph 1 2 3 4 ratsph 3.1 3.1 2.8 2.8
to the input file "tldau_3.in". But I got weird graph as shown.
I will be grateful if some body help me in this regard.
Thank you,
lamsalc
Re: DOS calculation of NiO using LDA (without PAW)
Posted: Fri Oct 28, 2011 4:26 pm
by jolafc
Hi,
If you modified the tldau_3.in file as you stated, I assume you obtained this .in :
Code: Select all
#Spin
nsppol 1
nspden 2
nspinor 1
spinat 0 0 1
0 0 -1
0 0 0
0 0 0
#Parameters
nstep 50
ecut 15
pawecutdg 30
iscf 17
toldfe 1.0d-5
nband 40
occopt 1
#tsmear 300 K
#Structural parameters
natom 4
ntypat 2
typat 1 1 2 2
znucl 28 8
xred 0 0 0
0.0 0.0 0.5
0.5 0.5 0.25
0.5 0.5 0.75
acell 3*7.92
rprim 0.0 1/2 1/2
1/2 0.0 1/2
1.0 1.0 0.0
# Kpoint Grid
ngkpt 2 2 2
chksymbreak 0 # The k point grid is not symmetric, but the calculations being for the ground-state, this is not a problem.
# LDA+U
usepawu 1
lpawu 2 -1
upawu 8.0 0.0 eV
jpawu 0.8 0.0 eV
#Density matrix
usedmatpu 5
dmatpawu
#Occupation matrix for spin 1 and atom 1
0.90036 0.00000 -0.00003 0.00000 0.00000
0.00000 0.90036 -0.00001 0.00000 0.00002
-0.00003 -0.00001 0.91309 -0.00001 0.00000
0.00000 0.00000 -0.00001 0.90036 -0.00002
0.00000 0.00002 0.00000 -0.00002 0.91309
#Occupation matrix for spin 1 and atom 2
0.89677 -0.00001 0.00011 -0.00001 0.00000
-0.00001 0.89677 0.00006 0.00001 -0.00010
0.00011 0.00006 0.11580 0.00006 0.00000
-0.00001 0.00001 0.00006 0.89677 0.00010
0.00000 -0.00010 0.00000 0.00010 0.11580
# add to conserve old < 6.7.2 behavior for calculating forces at each SCF step
optforces 1
prtdos 3
natsph 4
iatsph 1 2 3 4
ratsph 3.1 3.1 2.8 2.8
This calculation is (as tests should be) quite underconverged on many aspects to allow the test to run in a few seconds on a single processors. If you want meaningful results, several points need to be corrected :
1) The cutoff energies are too low. For Nickel, the values
should be replaced by
2) The tolerance on the total energy is high.
should be replaced by
(or less, but it can get difficult for an antiferromagnetic calculation)
3) Most importantly, you should use a muh finer k-point grid. Replace :
by (at least) :
and then, continue to converge this parameter to higher values.
Good luck!
Jonathan Laflamme Janssen
Re: DOS calculation of NiO using LDA (without PAW)
Posted: Tue Nov 01, 2011 10:32 pm
by lamsalc
Hi
Thank you very much for the reply.