[DFTB-Plus-User] bulk antiferromagnetic Fe2O3 calculation
Ulman Kanchan Ajit
kulman at ictp.it
Tue Mar 8 10:51:48 CET 2016
Dear All,
I'm trying to simulate bulk Fe2O3 using DFTB.
The magnetic structure of Fe2O3 is antiferromagnetic, with a magnetic
moment of about 4.5 muB on each Fe atom.
When I do a non-magnetic calculation for the bulk Fe2O3 structure, the scc
run converges and everything works out well. But when I turn on the
magnetism, the sccDFTB run just diverges.
Can anyone please point out the mistakes if any in the attached input file
and suggest me any other details I would need to run this calculation?
input:
--------------------------------------------
Geometry = GenFormat {
30 S
O Fe
1 1 1.7940998960 3.0894381120 0.8652210180
2 1 4.3520776210 1.3592721870 0.8652280770
3 1 1.5748565660 0.0090763820 0.8652633690
4 2 5.1315075790 2.9628083630 1.7323932470
5 2 0.0157066340 0.0091032660 2.3206062970
6 1 3.5723760160 2.9628742430 3.1877453210
7 1 0.7951193430 1.6126377320 3.1877823060
8 1 3.3531434700 -0.1175357420 3.1877845580
9 2 2.5735263150 1.4859861500 4.0549155610
10 2 5.1313441580 2.9629379400 4.6430922210
11 1 1.7940360310 0.1358021320 5.5102628600
12 1 4.1325370440 1.4860411470 5.5102940100
13 1 1.7939140650 2.8362303350 5.5102984280
14 2 0.0155998470 0.0091435770 6.3773587970
15 2 2.5735592430 1.4860484770 6.9657561560
16 1 3.5725336530 0.0091572100 7.8327972530
17 1 3.3530892150 3.0895719100 7.8328047880
18 1 0.7951712320 1.3593490820 7.8328309880
19 2 5.1315605350 2.9628718530 8.6999041120
20 2 0.0158709180 0.0091199260 9.2881842870
21 1 4.3521873560 1.6126352030 10.1552778240
22 1 1.7943049960 -0.1175516270 10.1553153980
23 1 1.5748582740 2.9628305560 10.1553222520
24 2 2.5738432510 1.4859692790 11.0224531080
25 2 5.1317391830 2.9628399390 11.6106140420
26 1 3.3533401370 0.1357179240 12.4778123840
27 1 1.0146941920 1.4859157100 12.4778147010
28 1 3.3532601810 2.8361808130 12.4778342950
29 2 0.0158666510 0.0090114190 13.3450673640
30 2 2.5736216510 1.4859494890 13.9331306240
0.0000000000 0.0000000000 0.0000000000
5.1158550570 -0.0000037340 -0.0000411300
2.5577847430 4.4306343540 -0.0000263230
-0.0000753660 0.0000022400 13.9351627090
}
Driver = ConjugateGradient {
MovedAtoms = 1:-1
MaxForceComponent = 1E-4
MaxSteps = 100
OutputPrefix = "Fe2O3-geom.out"
}
Hamiltonian = DFTB {
SCC = Yes
SCCTolerance = 1e-5
MaxSCCIterations = 500
SlaterKosterFiles = Type2FileNames {
Prefix = "./"
Separator = "-"
Suffix = ".skf"
}
MaxAngularMomentum {
Fe = "d"
O = "p"
}
SpinPolarisation = Colinear {
UnpairedElectrons = 4.0
InitialSpins = {
AtomSpin = {
Atoms = 4:5 14:15 24:25
SpinPerAtom = +1.0
}
AtomSpin = {
Atoms = 9:10 19:20 29:30
SpinPerAtom = -1.0
}
}
}
SpinConstants = {
Fe = {
# Wss Wsp Wsd*
-0.016 -0.012 -0.003
# Wps Wpp Wpd*
-0.012 -0.029 -0.001
# Wds Wdp Wdd
-0.003 -0.001 -0.015
}
O = {
# Wss Wsp
-0.035 -0.030
# Wps Wpp
-0.030 -0.028
}
}
Filling = MethfesselPaxton {
Temperature [Kelvin] = 235.0
Order = 2
}
KPointsAndWeights = SupercellFolding {
4 0 0
0 4 0
0 0 2
0.5 0.5 0.5
}
}
Analysis {
ProjectStates {
Region {
Atoms = Fe
ShellResolved = Yes
Label = "dos_fe"
}
Region {
Atoms = O
ShellResolved = Yes
Label = "dos_o"
}
}
}
ParserOptions {
ParserVersion = 4
}
--------------------------------------------
extract of output:
-------------------------------------------
142 -0.80671662E+02 -0.17424386E-03 0.55985563E-01
143 -0.80672143E+02 -0.48096275E-03 0.52970394E-01
144 -0.80673236E+02 -0.10923225E-02 0.47532973E-01
145 -0.80673733E+02 -0.49718076E-03 0.75032558E-01
146 -0.80637810E+02 0.35922583E-01 0.31044703E+00
147 -0.80621345E+02 0.16465358E-01 0.65880664E+00
148 -0.80558885E+02 0.62459742E-01 0.75809042E+00
149 -0.80543144E+02 0.15740971E-01 0.74600154E+00
150 -0.80597961E+02 -0.54817195E-01 0.61728913E+00
151 -0.80472169E+02 0.12579191E+00 0.56246009E+00
152 -0.79011488E+02 0.14606813E+01 0.18795395E+01
153 -0.80741987E+02 -0.17304992E+01 0.32994451E+01
154 -0.64012825E+02 0.16729163E+02 0.42386439E+01
155 -0.79620674E+02 -0.15607849E+02 0.17158742E+02
156 0.22070436E+02 0.10169111E+03 0.43794372E+02
157 -0.68316069E+01 -0.28902043E+02 0.49103385E+02
158 0.23965873E+02 0.30797480E+02 0.86826602E+02
159 0.92785096E+02 0.68819223E+02 0.18174888E+03
160 0.19679854E+03 0.10401344E+03 0.18517700E+03
161 0.71020848E+02 -0.12577769E+03 0.39169114E+03
162 0.65735930E+02 -0.52849178E+01 0.62906975E+03
163 0.22444879E+03 0.15871286E+03 0.58186113E+03
164 0.31521673E+03 0.90767940E+02 0.11262128E+04
Total Energy: 246.2689858186 H
Total Mermin free energy: 246.2688991754 H
Volume: 0.213154E+04 au^3
Pressure: 0.408074E-01 au 0.120060E+13 Pa
ERROR!
-> SCC is NOT converged, maximal SCC iterations exceeded
-----------------------------------------
Thanks in advance for all the help,
Kanchan
----------------------------------------------------------
Dr. Kanchan Ulman
Post Doctoral Fellow,
Abdus Salam International Centre for Theoretical Physics,
Strada Costiera 34151, Trieste, Italy.
email: kulman at ictp.it, ulman.kanchan at gmail.com
----------------------------------------------------------
More information about the DFTB-Plus-User
mailing list