[CP2K-user] [CP2K:20404] Polarization calculation
Sue Park
sueparkchemist at gmail.com
Wed Jul 3 04:50:58 UTC 2024
Dear CP2K community,
I'm trying to learn how to calculate polarization using CP2K. I'm using
2x2x2 supercell of BaTiO3 to benchmark the polarization values compared to
other references and Quantum Espresso.
I'm using Berry phase method by setting *PERIODIC .TRUE. in MOMENTS* as
it's periodic system. And the output for the cubic structure looks like:
Dipole vectors are based on the periodic (Berry phase) operator.
They are defined modulo integer multiples of the cell matrix [Debye].
[X] [ 38.42563418 0.00000000 0.00000000 ] [i]
[Y]=[ 0.00000000 38.42563418 0.00000000 ]*[j]
[Z] [ 0.00000000 0.00000000 38.65618798 ] [k]
Dipole moment [Debye]
X= -0.1123396E-09 Y= -0.1123351E-09 Z= -0.1414722E-09 Total=
0.0000000
How I have been calculating the polarization value is: 1) As I'm only
interested in the polarization in z direction, I combined the two values
highlighted in green. And 2) I divide the values by the cell volume. 3) I
convert the unit to uC/cm^2. The issue with this method is that the
polarization of the cubic phase is not zero. I've been trying to figure
this out because the polarization value for cubic phase should be zero or
close to zero. And the zero polarization for cubic phase is reproduced by
Quantum Espresso:
VALUES OF POLARIZATION
~~~~~~~~~~~~~~~~~~~~~~
The calculation of phases done along the direction of vector 3
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 = 0.0000000 (mod 30.0953409) (e/Omega).bohr
P = 0.0000000 (mod 0.0088327) e/bohr^2
P = 0.0000000 (mod 0.5053585) C/m^2
The polarization direction is: ( 0.00000 , 0.00000 , 1.00000 )
What I'm confused with is that the difference between the values in the
dipole vectors and the dipole moment. Is either of them electronic
polarization (from Berry phase) and ionic polarization? Or is the dipole
moment in the bottom line calculated from the addition of the electronic
polarization (Berry phase) and the ionic polarization? Is there any
reference/literature that describes how CP2K operates the Berry phase
calculation?
Here's my input script:
&GLOBAL
PROJECT BTO
RUN_TYPE CELL_OPT
PRINT_LEVEL MEDIUM
&END GLOBAL
&FORCE_EVAL
! This one is used for cell optimization
STRESS_TENSOR ANALYTICAL
METHOD QS
&SUBSYS
&KIND Ba
ELEMENT Ba
BASIS_SET DZVP-MOLOPT-PBE-GTH-q10
POTENTIAL GTH-PBE-q10
&END KIND
&KIND Ti
ELEMENT Ti
BASIS_SET DZVP-MOLOPT-PBE-GTH-q12
POTENTIAL GTH-PBE-q12
&END KIND
&KIND O
ELEMENT O
BASIS_SET DZVP-MOLOPT-PBE-GTH-q6
POTENTIAL GTH-PBE-q6
&END KIND
&CELL
A 8.000000000 0.000000000 0.000000000
B 0.000000000 8.000000000 0.000000000
C 0.000000000 0.000000000 8.000000000
PERIODIC XYZ
&END CELL
&TOPOLOGY
COORD_FILE_FORMAT pdb
COORD_FILE_NAME BTO.pdb
&END
&END SUBSYS
&DFT
BASIS_SET_FILE_NAME BASIS_MOLOPT_UZH
POTENTIAL_FILE_NAME GTH_POTENTIALS
&QS
METHOD GPW
EPS_DEFAULT 1.0E-12
&END QS
&POISSON
PERIODIC XYZ
PSOLVER PERIODIC
&END
&XC
&XC_FUNCTIONAL
&PBE
&END PBE
&END
&VDW_POTENTIAL
POTENTIAL_TYPE PAIR_POTENTIAL
&PAIR_POTENTIAL
PARAMETER_FILE_NAME ../../dftd3.dat
TYPE DFTD3(BJ)
REFERENCE_FUNCTIONAL PBE
&END
&END VDW_POTENTIAL
&END XC
&MGRID
NGRIDS 4
CUTOFF 600
&END MGRID
&SCF
SCF_GUESS ATOMIC
EPS_SCF 1.0E-8
MAX_SCF 300
&MIXING
METHOD BROYDEN_MIXING
ALPHA 0.2
BETA 1.5
NBROYDEN 8
&END MIXING
&END SCF
&PRINT
&MO_CUBES
WRITE_CUBE .FALSE.
NHOMO 1
NLUMO 1
&END MO_CUBES
&MOMENTS MEDIUM
PERIODIC T
&END MOMENTS
&END PRINT
&END DFT
&PRINT
&FORCES ON
&END FORCES
&END PRINT
&END FORCE_EVAL
&MOTION
&CELL_OPT
TYPE DIRECT_CELL_OPT
MAX_ITER 300
OPTIMIZER BFGS #Most efficient minimizer, but only for 'small'
systems
&END CELL_OPT
&GEO_OPT
MAX_DR 0.003
MAX_FORCE 0.00045
RMS_DR 0.0015
RMS_FORCE 0.0003
MAX_ITER 200
OPTIMIZER BFGS
&BFGS
TRUST_RADIUS 0.25
&END BFGS
&END GEO_OPT
&END MOTION
Here's the input structure:
CRYST1 8.000 8.000 8.000 90.00 90.00 90.00 P 1 1
ATOM 1 Ba BTO A 1 0.000 0.000 0.000 1.00 0.00
Ba
ATOM 2 Ti BTO A 1 2.000 2.000 2.000 1.00 0.00
Ti
ATOM 3 O BTO A 1 0.000 2.000 2.000 1.00 0.00
O
ATOM 4 O BTO A 1 2.000 0.000 2.000 1.00 0.00
O
ATOM 5 O BTO A 1 2.000 2.000 0.000 1.00 0.00
O
ATOM 6 Ba BTO A 1 0.000 0.000 4.000 1.00 0.00
Ba
ATOM 7 Ti BTO A 1 2.000 2.000 6.000 1.00 0.00
Ti
ATOM 8 O BTO A 1 0.000 2.000 6.000 1.00 0.00
O
ATOM 9 O BTO A 1 2.000 0.000 6.000 1.00 0.00
O
ATOM 10 O BTO A 1 2.000 2.000 4.000 1.00 0.00
O
ATOM 11 Ba BTO A 1 0.000 4.000 0.000 1.00 0.00
Ba
ATOM 12 Ti BTO A 1 2.000 6.000 2.000 1.00 0.00
Ti
ATOM 13 O BTO A 1 0.000 6.000 2.000 1.00 0.00
O
ATOM 14 O BTO A 1 2.000 4.000 2.000 1.00 0.00
O
ATOM 15 O BTO A 1 2.000 6.000 0.000 1.00 0.00
O
ATOM 16 Ba BTO A 1 0.000 4.000 4.000 1.00 0.00
Ba
ATOM 17 Ti BTO A 1 2.000 6.000 6.000 1.00 0.00
Ti
ATOM 18 O BTO A 1 0.000 6.000 6.000 1.00 0.00
O
ATOM 19 O BTO A 1 2.000 4.000 6.000 1.00 0.00
O
ATOM 20 O BTO A 1 2.000 6.000 4.000 1.00 0.00
O
ATOM 21 Ba BTO A 1 4.000 0.000 0.000 1.00 0.00
Ba
ATOM 22 Ti BTO A 1 6.000 2.000 2.000 1.00 0.00
Ti
ATOM 23 O BTO A 1 4.000 2.000 2.000 1.00 0.00
O
ATOM 24 O BTO A 1 6.000 0.000 2.000 1.00 0.00
O
ATOM 25 O BTO A 1 6.000 2.000 0.000 1.00 0.00
O
ATOM 26 Ba BTO A 1 4.000 0.000 4.000 1.00 0.00
Ba
ATOM 27 Ti BTO A 1 6.000 2.000 6.000 1.00 0.00
Ti
ATOM 28 O BTO A 1 4.000 2.000 6.000 1.00 0.00
O
ATOM 29 O BTO A 1 6.000 0.000 6.000 1.00 0.00
O
ATOM 30 O BTO A 1 6.000 2.000 4.000 1.00 0.00
O
ATOM 31 Ba BTO A 1 4.000 4.000 0.000 1.00 0.00
Ba
ATOM 32 Ti BTO A 1 6.000 6.000 2.000 1.00 0.00
Ti
ATOM 33 O BTO A 1 4.000 6.000 2.000 1.00 0.00
O
ATOM 34 O BTO A 1 6.000 4.000 2.000 1.00 0.00
O
ATOM 35 O BTO A 1 6.000 6.000 0.000 1.00 0.00
O
ATOM 36 Ba BTO A 1 4.000 4.000 4.000 1.00 0.00
Ba
ATOM 37 Ti BTO A 1 6.000 6.000 6.000 1.00 0.00
Ti
ATOM 38 O BTO A 1 4.000 6.000 6.000 1.00 0.00
O
ATOM 39 O BTO A 1 6.000 4.000 6.000 1.00 0.00
O
ATOM 40 O BTO A 1 6.000 6.000 4.000 1.00 0.00
O
END
Any of your inputs would be greatly appreciated. Thank you for your time
and consideration in advance.
Best,
Sue
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