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[Turan Birol <tb283@cornell.edu>]

   Dear Sathya,

   how large are the values you obtain? I don't know for sure for
YMnO3, but certain perovskite compounds are known to have anomalously
large effective charges.

   Also, did you try to do the same calculation using the response
functions capabilities of abinit? Does that method give the same
results?

   Regards,
   Turan.

On Tue, Aug 25, 2009 at 9:18 AM,
sathya<sathya_sheela1985001@rediffmail.com> wrote:
> Dear All,
>             I am trying to find the born effective charge for cubic YMnO3 
> but
> am getting very high values from the output.I am moving 1% of the acell in 
> Bohr
> and calculating from the change in polarization for movement for the 
> positive
> and negative displacements fo Y Mn and O.I am attaching the input and part 
> of
> the O/P file. Any suggestions are welcome
>
> # Finite difference calculation of the Born effective charges of cubic ymno3
> # (M. Veithen, 29.4.2005)
> #
>
> #Definition of the different datasets
> #************************************
>
> ndtset 7
> jdtset 1 2 3 4 5 6 7
>
>     xcart1   0.0000000000E+00  0.0000000000E+00  0.0000000000E+00
>              3.6849500000E+00  3.6849500000E+00  3.6849500000E+00
>              3.6849500000E+00  3.6849500000E+00  0.0000000000E+00
>              4.5126131835E-16  3.6849500000E+00  3.6849500000E+00
>              3.6849500000E+00  2.2563065918E-16  3.6849500000E+00
>
>     xcart2   0.0736990000E+00  0.0000000000E+00  0.0000000000E+00
>              3.6849500000E+00  3.6849500000E+00  3.6849500000E+00
>              3.6849500000E+00  3.6849500000E+00  0.0000000000E+00
>              4.5126131835E-16  3.6849500000E+00  3.6849500000E+00
>              3.6849500000E+00  2.2563065918E-16  3.6849500000E+00
>
>
>     xcart3   -.0736990000E+00  0.0000000000E+00  0.0000000000E+00
>              3.6849500000E+00  3.6849500000E+00  3.6849500000E+00
>              3.6849500000E+00  3.6849500000E+00  0.0000000000E+00
>              4.5126131835E-16  3.6849500000E+00  3.6849500000E+00
>              3.6849500000E+00  2.2563065918E-16  3.6849500000E+00
>
>     xcart4   0.0000000000E+00  0.0000000000E+00  0.0000000000E+00
>              3.75864900000E+00  3.6849500000E+00  3.6849500000E+00
>              3.6849500000E+00  3.6849500000E+00  0.0000000000E+00
>              4.5126131835E-16  3.6849500000E+00  3.6849500000E+00
>              3.6849500000E+00  2.2563065918E-16  3.6849500000E+00
>
>     xcart5   0.0000000000E+00  0.0000000000E+00  0.0000000000E+00
>              3.6112510000E+00  3.6849500000E+00  3.6849500000E+00
>              3.6849500000E+00  3.6849500000E+00  0.0000000000E+00
>              4.5126131835E-16  3.6849500000E+00  3.6849500000E+00
>              3.6849500000E+00  2.2563065918E-16  3.6849500000E+00
>
>     xcart6   0.0000000000E+00  0.0000000000E+00  0.0000000000E+00
>              3.6849500000E+00  3.6849500000E+00  3.6849500000E+00
>              3.7586490000E+00  3.6849500000E+00  0.0000000000E+00
>              0.01000000000000  3.6849500000E+00  3.6849500000E+00
>              3.7586490000E+00  2.2563065918E-16  3.6849500000E+00
>
>     xcart7   0.0000000000E+00  0.0000000000E+00  0.0000000000E+00
>              3.6849500000E+00  3.6849500000E+00  3.6849500000E+00
>              3.6112510000E+00  3.6849500000E+00  0.0000000000E+00
>              -.01000000000000  3.6849500000E+00  3.6849500000E+00
>              3.6112510000E+00  2.2563065918E-16  3.6849500000E+00
>
>
> #Definition of the elementary cell
> #*********************************
>   acell  7.3699  7.3699  7.3699
> angdeg 90 90 90
> #Definition of the atoms
> #***********************
>   natom 5
>   ntypat 3
>   znucl 39  25  8
>  # spgroup  221
>   typat 1 2 3 3 3
>   ixc 1
>
> #Definition of the SCF procedure
> #*******************************
>   iscf 5
>   nstep 1000
>
>
> #Definition of the plane wave basis set
> #**************************************
>   ecut  40
>   ecutsm 0.5
>   dilatmx 1.05
>   kptopt 1
>   ngkpt 6 6 6
>   shiftk  0 0 0
>    toldfe 1.0d-4
>
> # Berry phase calculation of the polarization
> #********************************************
>   berryopt -1
>   rfdir 1 1 1
>
>
> for Y movement in xred=.01 or xcart=.073699 movement is in x axis
>
>  Polarization in cartesian coordinates (a.u.):
>  (the sum of the electronic and ionic Berry phase has been fold into [-1, 
> 1])
>     Electronic berry phase:       -0.648502226E-03   0.519926305E-02
> 0.418131244E-02
>     Expectation value (PAW only):  0.000000000E+00   0.000000000E+00
> 0.000000000E+00
>     Ionic:                        -0.865315868E-02  -0.920548796E-02
> -0.920548796E-02
>     Total:                        -0.930166091E-02  -0.400622491E-02
> -0.502417551E-02
>
>  Polarization in cartesian coordinates (C/m^2):
>  (the sum of the electronic and ionic Berry phase has been fold into [-1, 
> 1])
>     Electronic berry phase:       -0.371039002E-01   0.297474595E+00
> 0.239232794E+00
>     Expectation value (PAW only):  0.000000000E+00   0.000000000E+00
> 0.000000000E+00
>     Ionic:                        -0.495088410E+00  -0.526689798E+00
> -0.526689798E+00
>     Total:                        -0.532192310E+00  -0.229215203E+00
> -0.287457004E+00
>
> for Y movement in xred=-.01 or xcart=-.073699 movement is in x axis
>
> Polarization in cartesian coordinates (a.u.):
>  (the sum of the electronic and ionic Berry phase has been fold into [-1, 
> 1])
>     Electronic berry phase:       -0.599410096E-02   0.655736562E-02
> 0.755351557E-02
>     Expectation value (PAW only):  0.000000000E+00   0.000000000E+00
> 0.000000000E+00
>     Ionic:                        -0.975781723E-02  -0.920548796E-02
> -0.920548796E-02
>     Total:                        -0.157519182E-01  -0.264812233E-02
> -0.165197238E-02
>
>  Polarization in cartesian coordinates (C/m^2):
>  (the sum of the electronic and ionic Berry phase has been fold into [-1, 
> 1])
>     Electronic berry phase:       -0.342951057E+00   0.375178110E+00
> 0.432172592E+00
>     Expectation value (PAW only):  0.000000000E+00   0.000000000E+00
> 0.000000000E+00
>     Ionic:                        -0.558291186E+00  -0.526689798E+00
> -0.526689798E+00
>     Total:                        -0.901242243E+00  -0.151511688E+00
> -0.945172059E-01
>
>
> for Mn movement in xred=0.01 or xcart=0.073699 movement is in x axis
>
>  Polarization in cartesian coordinates (a.u.):
>  (the sum of the electronic and ionic Berry phase has been fold into [-1, 
> 1])
>     Electronic berry phase:       -0.139476229E-02   0.937705312E-03
> -0.206983548E-02
>     Expectation value (PAW only):  0.000000000E+00   0.000000000E+00
> 0.000000000E+00
>     Ionic:                        -0.791671964E-02  -0.920548796E-02
> -0.920548796E-02
>     Total:                        -0.931148193E-02  -0.826778265E-02
> -0.112753234E-01
>
>  Polarization in cartesian coordinates (C/m^2):
>  (the sum of the electronic and ionic Berry phase has been fold into [-1, 
> 1])
>     Electronic berry phase:       -0.798009917E-01   0.536505857E-01
> -0.118425143E+00
>     Expectation value (PAW only):  0.000000000E+00   0.000000000E+00
> 0.000000000E+00
>     Ionic:                        -0.452953226E+00  -0.526689798E+00
> -0.526689798E+00
>     Total:                        -0.532754218E+00  -0.473039212E+00
> -0.645114941E+00
>
>
> for Mn movement in xred=-.01 or xcart=-.073699 movement is in x axis
>
>  Polarization in cartesian coordinates (a.u.):
>  (the sum of the electronic and ionic Berry phase has been fold into [-1, 
> 1])
>     Electronic berry phase:        0.693042190E-02   0.284576891E-02
> 0.281335699E-02
>     Expectation value (PAW only):  0.000000000E+00   0.000000000E+00
> 0.000000000E+00
>     Ionic:                        -0.104942563E-01  -0.920548796E-02
> -0.920548796E-02
>     Total:                        -0.356383437E-02  -0.635971905E-02
> -0.639213097E-02
>
>  Polarization in cartesian coordinates (C/m^2):
>  (the sum of the electronic and ionic Berry phase has been fold into [-1, 
> 1])
>     Electronic berry phase:        0.396522436E+00   0.162819989E+00
> 0.160965549E+00
>     Expectation value (PAW only):  0.000000000E+00   0.000000000E+00
> 0.000000000E+00
>     Ionic:                        -0.600426369E+00  -0.526689798E+00
> -0.526689798E+00
>     Total:                        -0.203903933E+00  -0.363869808E+00
> -0.365724249E+00
>
>
>
> for O movement in xred=+.01 or xcart=+.073699 movement is in x axis
>
>  Polarization in cartesian coordinates (a.u.):
>  (the sum of the electronic and ionic Berry phase has been fold into [-1, 
> 1])
>     Electronic berry phase:       -0.312615041E-02   0.633696057E-02
> 0.642407623E-02
>     Expectation value (PAW only):  0.000000000E+00   0.000000000E+00
> 0.000000000E+00
>     Ionic:                        -0.684628299E-02  -0.920548796E-02
> -0.920548796E-02
>     Total:                        -0.997243339E-02  -0.286852738E-02
> -0.278141173E-02
>
>  Polarization in cartesian coordinates (C/m^2):
>  (the sum of the electronic and ionic Berry phase has been fold into [-1, 
> 1])
>     Electronic berry phase:       -0.178861950E+00   0.362567688E+00
> 0.367551989E+00
>     Expectation value (PAW only):  0.000000000E+00   0.000000000E+00
> 0.000000000E+00
>     Ionic:                        -0.391708448E+00  -0.526689798E+00
> -0.526689798E+00
>     Total:                        -0.570570398E+00  -0.164122110E+00
> -0.159137809E+00
>
>
> for O movement in xred=-.01 or xcart=-.073699 movement is in x axis
>
>  Polarization in cartesian coordinates (a.u.):
>  (the sum of the electronic and ionic Berry phase has been fold into [-1, 
> 1])
>     Electronic berry phase:        0.506685030E-02   0.123537138E-03
> -0.389953469E-02
>     Expectation value (PAW only):  0.000000000E+00   0.000000000E+00
> 0.000000000E+00
>     Ionic:                        -0.115646929E-01  -0.920548796E-02
> -0.920548796E-02
>     Total:                        -0.649784263E-02  -0.908195082E-02
> -0.131050226E-01
>
>  Polarization in cartesian coordinates (C/m^2):
>  (the sum of the electronic and ionic Berry phase has been fold into [-1, 
> 1])
>     Electronic berry phase:        0.289898631E+00   0.706814788E-02
> -0.223110947E+00
>     Expectation value (PAW only):  0.000000000E+00   0.000000000E+00
> 0.000000000E+00
>     Ionic:                        -0.661671147E+00  -0.526689798E+00
> -0.526689798E+00
>     Total:                        -0.371772516E+00  -0.519621650E+00
> -0.749800745E+00
>
>
> Thank you in advance for any suggestions  and sorry for the long file.
>
> Regards
> Sathya Sheela.S
> Grad student
> National Institute of Technology
> Trichy ,India
>