[Pw_forum] Use of wannier90.x for the calculation of Born Effective Charge
yukihiro_okuno at fujifilm.co.jp
yukihiro_okuno at fujifilm.co.jp
Thu Jul 30 04:00:53 CEST 2009
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.
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