You refer to an older version of BerryPI, which I do not have in place. I am
inclined to think that the total phase is _not_ wrapped, but it would help to
see your output tables (as below) before giving the exact answer. (please post
to the list)
As of WIEN2k v21, ionic and electronic phases are not added up, instead the
corresponding polarizations are after converting into Cartesian coordinate. It
is needed for generic (non-orthogonal) lattice vectors. This is how the new
output (BaTiO3 tutorial) looks like:
....
CALCULATION OF ELECTRONIC POLARIZATION (primitive lattice coordinates)
=======================================================================================
Value | spin | dir(1) | dir(2) |
dir(3)
---------------------------------------------------------------------------------------
Berry phase wrapped (rad) sp(1) [-2.660094e-13, 3.450573e-13,
1.258913e+00]
Berry phase (rad) up+dn [-5.320189e-13, 6.901146e-13,
2.517826e+00]
Berry phase wrapped (rad) up+dn [-5.320189e-13, 6.901146e-13,
2.517826e+00]
Electronic polarization (C/m2) sp(1) [-8.415856e-14, 1.091673e-13,
4.024760e-01]
=======================================================================================
The electronic polarization vector is presented in this coord. system:
dir(1) = [ 7.547566e+00, 4.621551e-16, 4.621551e-16] bohr
dir(2) = [ 0.000000e+00, 7.547566e+00, 4.621551e-16] bohr
dir(3) = [ 0.000000e+00, 0.000000e+00, 7.626934e+00] bohr
and will be transformed into Cartesian coordinates.
CALCULATION OF IONIC POLARIZATION (conventional lattice coordinates)
=======================================================================================
Elem.| Fractional coord. | spin | Zion | dir(1) | dir(2) |
dir(3)
---------------------------------------------------------------------------------------
+------------ Ionic phase (rad)
------------+
Ba (0.0000, 0.0000, 0.0000) sp(1) 10.00 [ 0.000000e+00, 0.000000e+00,
0.000000e+00]
Ti (0.5000, 0.5000, 0.5152) sp(1) 12.00 [ 3.769911e+01, 3.769911e+01,
3.884323e+01]
O (0.5000, 0.5000, 0.9736) sp(1) 6.00 [ 1.884956e+01, 1.884956e+01,
3.670240e+01]
O (0.5000, 0.0000, 0.4834) sp(1) 6.00 [ 1.884956e+01, 0.000000e+00,
1.822516e+01]
O (0.0000, 0.5000, 0.4834) sp(1) 6.00 [ 0.000000e+00, 1.884956e+01,
1.822516e+01]
---------------------------------------------------------------------------------------
Total ionic phase (rad) sp(1) [ 7.539822e+01, 7.539822e+01,
1.119960e+02]
Total ionic phase wrap. (rad) sp(1) [ 3.552714e-15, 3.552714e-15,
-1.101384e+00]
Ionic polarization (C/m2) sp(1) [ 5.619937e-16, 5.619937e-16,
-1.760570e-01]
=======================================================================================
The ionic positions and associated polarization vector is presented in this
coord. system:
dir(1) = [ 7.547566e+00, 4.621551e-16, 4.621551e-16] bohr
dir(2) = [ 0.000000e+00, 7.547566e+00, 4.621551e-16] bohr
dir(3) = [ 0.000000e+00, 0.000000e+00, 7.626934e+00] bohr
SUMMARY OF POLARIZATION CALCULATION IN CARTESIAN COORDINATES
=======================================================================================
Value | spin | X | Y |
Z
---------------------------------------------------------------------------------------
Electronic polarization (C/m2) sp(1) [-8.415856e-14, 1.091673e-13,
4.024760e-01]
Ionic polarization (C/m2) sp(1) [ 5.619937e-16, 5.619937e-16,
-1.760570e-01]
Tot. spin polariz.=Pion+Pel (C/m2) sp(1) [-8.359656e-14, 1.097293e-13,
2.264190e-01]
---------------------------------------------------------------------------------------
TOTAL POLARIZATION (C/m2) both [-8.359656e-14, 1.097293e-13,
2.264190e-01]
=======================================================================================
As one can see, there is no "Total phase" only "Tot. spin polariz.=Pion+Pel".
I hope it will help
Oleg
________________________________________
From: Wien <[email protected]> on behalf of shahrbano
rahimi <[email protected]>
Sent: Friday, May 28, 2021 12:31
To: [email protected]
Subject: [Wien] wrap
Dear Prof. Rubel Oleg and WIEN2k users,
I have a general question concerning Berry phase calculations.
Would you, please, let me know that in the BerryPI package whether only the
ionic and electronic parts of the phase are wrapped into the [-pi, pi] or the
total phase is also wrapped into this interval. By this I mean that if the
total phase after summing the wrapped ionic and electronic parts became larger
than pi or smaller than -pi, whether the BerryPI package also wraps the total
phase into the interval [-pi, pi] or leaves it to be located outside of the
interval?
The BerryPI version: 1.4.0 (May 25, 2018)
The Wien2k version:18.2
Sincerely,
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