[Pw_forum] regarding born-effective charge

[xirainbow]

You can add "  epsil=.true.," in Gamma-point phonon calculation. And
then the BECs will be calculated automatically with DFPT.

On Thu, Feb 20, 2014 at 11:49 AM,  <himanshu at iopb.res.in> wrote:
> --------------------------
> --------------------------------------------------------------------------
>
> Respected QE users,
>                     I tried to perform Born-effective charge calculation
> according to the procedure given in example10 of
> Example Directory. I first did scf calculation by
> displacing 0.05Angstrom one of the atom along x-axis
> and then did nscf calculation with options
> lberry=.true.,gdr=1 and nppstr=70.
>
>                     but i am getting NAN value, here is the output
>
>           VALUES OF POLARIZATION
>                              ~~~~~~~~~~~~~~~~~~~~~~
>
>         The calculation of phases done along the direction of vector 1
>         of the reciprocal lattice gives the following contribution to
>         the polarization vector (in different units, and being Omega
>         the volume of the unit cell):
>
>            P =         NaN  (mod   8.2766587)  (e/Omega).bohr
>
>            P =         NaN  (mod   0.0033970)  e/bohr^2
>
>            P =         NaN  (mod   0.1942150)  C/m^2
>
>         The polarization direction is:  ( 1.00000 , 0.00000 , -.00000 )
>
>          System has 1.32eV band gap also. could you please suggest me how
> to get the correct value of Born-effective charge.
>
> Regards
> Himanshu
> IOPB
>
>
>
>
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum



-- 
____________________________________
Hui Wang
School of physics, Henan University of Science and Technology, Henan, China