ABINIT Discussion Forums

Dear All,

I am attempting to run a calculation of cubic perovskite BaTiO3 in a finite electric field (latest 7.8.2 version). I run the calculation in two steps as per the tutorial first a calculation with berryopt -1 then berryopt 4 for the case of finite electric field. The input file is below and converges well when I use norm-conserving HGH pseudos, but fails to converge for either LDA or PBE PAW potentials.

The input file is:
#Definition of the unit cell
acell 3*1.0 # This is equivalent to 10.18 10.18 10.18
rprim 7.48494946235727E+00 -8.88264036738449E-03 -8.85778459431047E-03
1.21503327618304E-02 7.48494487135946E+00 -8.85778459431047E-03
1.21503327618304E-02 1.21162376506412E-02 7.48494030593899E+00


#Definition of the atom types
ntypat 3 # There is only one type of atom
znucl 56 22 8 # The keyword "znucl" refers to the atomic number of the
# possible type(s) of atom. The pseudopotential(s)
# mentioned in the "files" file must correspond
# to the type(s) of atom. Here, the only type is Silicon.


#Definition of the atoms
natom 5 # There are two atoms
typat 1 2 3 3 3 # They both are of type 1, that is, Silicon.
xred # This keyword indicate that the location of the atoms
# will follow, one triplet of number for each atom
0.000046759387 0.000046759387 0.000046759387
0.490710702514 0.490710702514 0.490710702514
0.510846952654 0.510846952654 0.015848667792
0.015848667792 0.510846952654 0.510846952654
0.510846952654 0.015848667792 0.510846952654

#Grid definitions
paral_kgb 0
pawecutdg 50.
nbdbuf 0
ecut 20.
ecutsm 0.5

#SCF cycle parameters
tolvrs 1.0d-10
nstep 60

#K-points and sym
kptopt 1
symmorphi 0
nsym 0
occopt 1
ngkpt 6 6 6
nshiftk 1
# shiftk 0.5 0.5 0.5

#Polarization and electric field
ndtset 2
jdtset 11
21

nband11 30
nband21 20

berryopt11 -1 rfdir11 1 1 1

berryopt21 4 efield21 0.0001 0.0001 0.0001 getwfk21 11

---

I have run this calculation with HGH pseudos where the .files file is:
BaTiO3.in
BaTiO3.out
BaTiO3_i
BaTiO3_o
BaTiO3_tmp
/home/david/Programs/ABINIT/Pseudos/LDA_HGH/56ba.10.hgh
/home/david/Programs/ABINIT/Pseudos/LDA_HGH/22ti.12.hgh
/home/david/Programs/ABINIT/Pseudos/LDA_HGH/8o.6.hgh

The energy convergence for the finite field calculation looks like:
ETOT 1 -131.95905135155 -1.320E+02 1.264E+08 8.006E+02
ETOT 2 -131.90352561804 5.553E-02 1.026E+07 1.151E+03
ETOT 3 -132.04694787176 -1.434E-01 7.548E+04 2.134E+01
ETOT 4 -132.05199325504 -5.045E-03 5.123E+04 8.804E+00
ETOT 5 -132.05272027456 -7.270E-04 1.479E+02 7.297E+00
ETOT 6 -132.05345580480 -7.355E-04 1.972E+01 1.159E+00
ETOT 7 -132.05337135492 8.445E-05 1.572E+00 2.242E+00
ETOT 8 -132.05348470910 -1.134E-04 5.473E-02 9.222E-01
ETOT 9 -132.05357456780 -8.986E-05 8.404E-04 1.237E-01
ETOT 10 -132.05359054584 -1.598E-05 6.254E-06 5.779E-03
ETOT 11 -132.05359203164 -1.486E-06 1.163E-06 3.806E-03
ETOT 12 -132.05359259337 -5.617E-07 3.042E-07 7.004E-04
ETOT 13 -132.05359261814 -2.477E-08 3.578E-07 8.075E-04
ETOT 14 -132.05359275593 -1.378E-07 1.601E-07 5.279E-05
ETOT 15 -132.05359277517 -1.924E-08 1.870E-07 2.656E-05
ETOT 16 -132.05359278519 -1.002E-08 1.316E-07 3.379E-06
ETOT 17 -132.05359278710 -1.914E-09 1.344E-07 4.490E-06
ETOT 18 -132.05359278880 -1.695E-09 1.274E-07 7.337E-07
ETOT 19 -132.05359278936 -5.657E-10 1.283E-07 1.545E-07
ETOT 20 -132.05359278958 -2.150E-10 1.272E-07 1.255E-07
ETOT 21 -132.05359278967 -8.905E-11 1.276E-07 3.081E-07
ETOT 22 -132.05359278972 -5.005E-11 1.274E-07 2.070E-07
ETOT 23 -132.05359278973 -7.191E-12 1.275E-07 3.602E-07
ETOT 24 -132.05359278974 -1.245E-11 1.275E-07 2.984E-07
ETOT 25 -132.05359278976 -1.702E-11 1.276E-07 1.149E-07
ETOT 26 -132.05359278972 3.701E-11 1.276E-07 2.933E-07
ETOT 27 -132.05359278974 -1.955E-11 1.276E-07 1.919E-07
ETOT 28 -132.05359278976 -2.515E-11 1.277E-07 6.243E-08
ETOT 29 -132.05359278976 1.705E-13 1.277E-07 7.279E-08
ETOT 30 -132.05359278976 7.674E-13 1.277E-07 1.107E-07

However, if I use PAW with a .files:
BaTiO3.in
BaTiO3.out
BaTiO3_i
BaTiO3_o
BaTiO3_tmp
/home/david/Programs/ABINIT/PAW/LDA_PW_JTH/Ba.LDA_PW-JTH.xml
/home/david/Programs/ABINIT/PAW/LDA_PW_JTH/Ti.LDA_PW-JTH.xml
/home/david/Programs/ABINIT/PAW/LDA_PW_JTH/O.LDA_PW-JTH.xml

In this case the convergence is never achieved for the finite field case as below:
ETOT 1 -133.51808877219 -1.335E+02 2.027E+05 6.163E+00
ETOT 2 -133.52473157185 -6.643E-03 7.118E+00 9.366E+00
ETOT 3 -133.50895268021 1.578E-02 6.828E-01 6.098E-01
ETOT 4 -133.50943337791 -4.807E-04 1.906E-01 1.099E-01
ETOT 5 -133.50931674399 1.166E-04 6.862E-02 6.509E-02
ETOT 6 -133.50898665253 3.301E-04 2.047E-02 4.229E-03
ETOT 7 -133.50891766749 6.899E-05 1.587E-02 3.990E-04
ETOT 8 -133.50918541504 -2.677E-04 2.918E-03 3.653E-04
ETOT 9 -133.50917242038 1.299E-05 6.107E-03 2.619E-04
ETOT 10 -133.50873499631 4.374E-04 1.383E-02 7.473E-04
ETOT 11 -133.50911141865 -3.764E-04 1.022E-02 1.332E-04
ETOT 12 -133.50913452968 -2.311E-05 9.061E-03 1.628E-05
ETOT 13 -133.50915196808 -1.744E-05 1.174E-02 1.084E-05
ETOT 14 -133.50920602029 -5.405E-05 7.601E-03 3.938E-05
ETOT 15 -133.50913462834 7.139E-05 5.091E-03 3.187E-05
ETOT 16 -133.50829220336 8.424E-04 1.570E-02 2.754E-03
ETOT 17 -133.50874542848 -4.532E-04 2.042E-02 2.135E-05
ETOT 18 -133.50869665413 4.877E-05 8.919E-03 2.030E-04
ETOT 19 -133.50882329615 -1.266E-04 9.436E-03 2.311E-05
ETOT 20 -133.50911665952 -2.934E-04 6.567E-03 1.899E-05
ETOT 21 -133.50893632783 1.803E-04 1.749E-02 1.028E-04
ETOT 22 -133.50902918109 -9.285E-05 1.763E-02 3.238E-05
ETOT 23 -133.50918362566 -1.544E-04 6.888E-03 2.599E-05
ETOT 24 -133.50919227394 -8.648E-06 1.215E-02 1.525E-05
ETOT 25 -133.50891030694 2.820E-04 6.612E-03 3.204E-04
ETOT 26 -133.50911240090 -2.021E-04 1.309E-02 5.831E-05
ETOT 27 -133.50910567770 6.723E-06 6.719E-03 1.218E-05
ETOT 28 -133.50879731791 3.084E-04 1.628E-02 7.156E-04
ETOT 29 -133.50889774000 -1.004E-04 9.074E-03 3.622E-05
ETOT 30 -133.50907638150 -1.786E-04 1.786E-02 3.412E-05
ETOT 31 -133.50910604413 -2.966E-05 7.235E-03 1.807E-05
ETOT 32 -133.50904306076 6.298E-05 1.331E-02 2.955E-05
ETOT 33 -133.50852907296 5.140E-04 2.480E-02 4.952E-04
ETOT 34 -133.50873782657 -2.088E-04 1.020E-02 2.235E-05
ETOT 35 -133.50872702915 1.080E-05 1.001E-02 2.165E-04
ETOT 36 -133.50906587921 -3.389E-04 1.548E-02 1.579E-05
ETOT 37 -133.50867302356 3.929E-04 1.657E-02 5.020E-04
ETOT 38 -133.50895038209 -2.774E-04 9.188E-03 9.924E-05
ETOT 39 -133.50895730360 -6.922E-06 1.409E-02 1.493E-05
ETOT 40 -133.50898537018 -2.807E-05 9.484E-03 2.259E-04
ETOT 41 -133.50909240027 -1.070E-04 7.599E-03 8.296E-06
ETOT 42 -133.50906011723 3.228E-05 1.335E-02 1.056E-05
ETOT 43 -133.50918720657 -1.271E-04 1.137E-02 3.838E-06
ETOT 44 -133.50879356812 3.936E-04 2.668E-02 2.018E-04
ETOT 45 -133.50921273663 -4.192E-04 4.335E-03 9.461E-05
ETOT 46 -133.50888578309 3.270E-04 1.027E-02 4.023E-05
ETOT 47 -133.50919343467 -3.077E-04 9.487E-03 7.094E-06
ETOT 48 -133.50876928432 4.242E-04 1.199E-02 3.956E-04
ETOT 49 -133.50900162375 -2.323E-04 6.834E-03 6.492E-05
ETOT 50 -133.50914517658 -1.436E-04 8.413E-03 6.596E-06
ETOT 51 -133.50867299643 4.722E-04 1.370E-02 7.212E-04
ETOT 52 -133.50908904491 -4.160E-04 6.116E-03 1.211E-05
ETOT 53 -133.50917767559 -8.863E-05 1.194E-02 1.713E-05
ETOT 54 -133.50917734457 3.310E-07 5.341E-03 2.204E-05
ETOT 55 -133.50906866680 1.087E-04 1.070E-02 1.838E-05
ETOT 56 -133.50910004009 -3.137E-05 7.396E-03 5.354E-06
ETOT 57 -133.50889863626 2.014E-04 1.133E-02 1.599E-04
ETOT 58 -133.50902864384 -1.300E-04 1.451E-02 2.965E-06
ETOT 59 -133.50900598698 2.266E-05 6.167E-03 2.018E-04
ETOT 60 -133.50912386003 -1.179E-04 8.319E-03 5.910E-06

I've tried increasing ecut and pawecutdg as well as changing the mixing to iscf 7. However, none of these methods help. Any hints would be much appreciated.

David.

Hi,

I've just perform exactly the same calculation on an other perovskite in PAW and it worked. I also used the JTH v0.2 table to get de Aftomic data files.
My results are comparable to literature so be sure that it works.

Note that you calculation in NC is converging but did not reach your tolerance critera (tolvrs 1e-10) and stop at the default value of nstep=30.

You may want to try all the input varaibles that improve convergence scheme and why not increase a little bit you k-mesh grid.

Cheers

Jordan

Dear Jordan,

Thanks for replying. I have tried tweaking several variables, but the convergence in the presence of electric fields never improves. Would you be able to share some details of your input file with me?

Thanks,
David