Dear PWSCF users. I'm now using wannier90.x in PWSCF package (espresso-4.1) for
the calculation of Born Effective charge for each orbital like N.Marzari and D. Vanderbilt http:/arxiv.org/abs/cond-mat/9802210. I employ the example of BaTiO3. For cubic symmetry (centro symmetric atomic position), the calculation is done with reasonable results. But, in order to calculate the Ti's Born effective charge , I displacing the Ti atom, like ( 0.5 0.5 0.505) from the centro-symmetric position (0.5,0.5,0.5), the error occurred in the calculation of pw2wannier.x with the message below, Something wrong numk = 64 iknum= 130. This is due to that the symmetry is lowered by the displacement of Ti atom and the k-points are added in the non-SCF calculation in PWSCF (in the subroutine sgama). If we set nosym in the input file of non-SCF calculation with k-points is same as BaTiO3.win file., the symmetry of the results of wannier center broken, so the calculated Born Effective Charges are wrong. How should treat the k-points inconsistent when we calculate the Born effective charge in displacing the atom. Here is my input file for BaTiO3.win. num_wann = 9 num_iter = 100 !here we exclude all bands except the O2p bands exclude_bands : 1,2,3,4,5,6,7,8,9,10,11 write_xyz = T guiding_centres = T begin atoms_frac Ba 0.0 0.0 0.0 Ti 0.5 0.5 0.502 O 0.0 0.5 0.5 O 0.5 0.5 0.0 O 0.5 0.0 0.5 end atoms_frac begin kpoint_path L 0.50000 0.50000 0.5000 G 0.00000 0.00000 0.0000 G 0.00000 0.00000 0.0000 X 0.50000 0.00000 0.5000 X 0.50000 -0.50000 0.0000 K 0.37500 -0.37500 0.0000 K 0.37500 -0.37500 0.0000 G 0.00000 0.00000 0.0000 end kpoint_path bands_plot =T !!To plot the WF !restart = plot !wannier_plot = true !wannier_plot_supercell = 2 !wannier_plot_list = 3 begin projections O:p end projections begin unit_cell_cart bohr 7.44266 0.0 0.0 0.0 7.44266 0.0 0.0 0.0 7.44266 end unit_cell_cart mp_grid : 4 4 4 begin kpoints 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.25000000 0.00000000 0.00000000 0.50000000 0.00000000 0.00000000 0.75000000 0.00000000 0.25000000 0.00000000 0.00000000 0.25000000 0.25000000 0.00000000 0.25000000 0.50000000 0.00000000 0.25000000 0.75000000 0.00000000 0.50000000 0.00000000 0.00000000 0.50000000 0.25000000 0.00000000 0.50000000 0.50000000 0.00000000 0.50000000 0.75000000 0.00000000 0.75000000 0.00000000 0.00000000 0.75000000 0.25000000 0.00000000 0.75000000 0.50000000 0.00000000 0.75000000 0.75000000 0.25000000 0.00000000 0.00000000 0.25000000 0.00000000 0.25000000 0.25000000 0.00000000 0.50000000 0.25000000 0.00000000 0.75000000 0.25000000 0.25000000 0.00000000 0.25000000 0.25000000 0.25000000 0.25000000 0.25000000 0.50000000 0.25000000 0.25000000 0.75000000 0.25000000 0.50000000 0.00000000 0.25000000 0.50000000 0.25000000 0.25000000 0.50000000 0.50000000 0.25000000 0.50000000 0.75000000 0.25000000 0.75000000 0.00000000 0.25000000 0.75000000 0.25000000 0.25000000 0.75000000 0.50000000 0.25000000 0.75000000 0.75000000 0.50000000 0.00000000 0.00000000 0.50000000 0.00000000 0.25000000 0.50000000 0.00000000 0.50000000 0.50000000 0.00000000 0.75000000 0.50000000 0.25000000 0.00000000 0.50000000 0.25000000 0.25000000 0.50000000 0.25000000 0.50000000 0.50000000 0.25000000 0.75000000 0.50000000 0.50000000 0.00000000 0.50000000 0.50000000 0.25000000 0.50000000 0.50000000 0.50000000 0.50000000 0.50000000 0.75000000 0.50000000 0.75000000 0.00000000 0.50000000 0.75000000 0.25000000 0.50000000 0.75000000 0.50000000 0.50000000 0.75000000 0.75000000 0.75000000 0.00000000 0.00000000 0.75000000 0.00000000 0.25000000 0.75000000 0.00000000 0.50000000 0.75000000 0.00000000 0.75000000 0.75000000 0.25000000 0.00000000 0.75000000 0.25000000 0.25000000 0.75000000 0.25000000 0.50000000 0.75000000 0.25000000 0.75000000 0.75000000 0.50000000 0.00000000 0.75000000 0.50000000 0.25000000 0.75000000 0.50000000 0.50000000 0.75000000 0.50000000 0.75000000 0.75000000 0.75000000 0.00000000 0.75000000 0.75000000 0.25000000 0.75000000 0.75000000 0.50000000 0.75000000 0.75000000 0.75000000 end kpoints Sincerely.
