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