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[Philippe GHOSEZ <Philippe.Ghosez@ulg.ac.be>]

Dear Sathya,

did you check if such system is insulating at the LDA level  ?
Typical calculations  requires LSDA+U  ...

Best wishes,

Philippe.


On 25 Aug 2009, at 15:18, sathya 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