[CP2K-user] [CP2K:19978] Does the boundary setting affect the charge distribution under the electric field?
Evelyn Navarro
easauasqc at gmail.com
Thu Feb 29 14:33:26 UTC 2024
Hi
I tried to use the periodic electric field to calculate the two-dimensional
piezoelectric material at the periodic boundary, but the charge seemed to
accumulate towards the middle of the two-dimensional material, which was
unreasonable. The normal ones should gather towards both ends of the
material. I want to know what the problem is. (This does not seem to be a
problem with aperiodic boundaries.)
&GLOBAL
PROJECT 468-zhouqi-0.003d-xyzbianjie-2024-M-EWALD
PRINT_LEVEL LOW
RUN_TYPE MD
&END GLOBAL
&FORCE_EVAL
METHOD Quickstep
&SUBSYS
&CELL
ABC 38.9946780817 32.5196269485 100.000
PERIODIC XYZ #Direction of applied PBC (geometry aspect)
&END CELL
&TOPOLOGY
COORD_FILE_FORMAT XYZ
COORD_FILE_NAME 468.xyz
&CENTER_COORDINATES #Centering the atoms in the box
&END
&END
# &VELOCITY #You can set initial atomic velocities in this section
# &END VELOCITY
&END SUBSYS
&DFT
# WFN_RESTART_FILE_NAME 400-RESTART.wfn
CHARGE 0 #Net charge
MULTIPLICITY 1 #Spin multiplicity
&PERIODIC_EFIELD
INTENSITY 0.003
POLARISATION -1.00000 0.00000 0.00000
&END
&QS
EPS_DEFAULT 1E-10 #This is default. Set all EPS_xxx to values such
that the energy will be correct up to this value
EXTRAPOLATION ASPC #Extrapolation for wavefunction during e.g. MD.
ASPC is default, PS also be used
EXTRAPOLATION_ORDER 3 #Order for PS or ASPC extrapolation. 3 is
default
METHOD xTB
&xTB
DO_EWALD T
CHECK_ATOMIC_CHARGES F #xTB calculation often crashes without
setting this to false
&PARAMETER
DISPERSION_PARAMETER_FILE dftd3.dat
PARAM_FILE_NAME xTB_parameters
&END PARAMETER
&END xTB
&END QS
&POISSON
&EWALD
ALPHA 1.0
EWALD_TYPE SPME
GMAX 75
&END EWALD
PERIODIC XYZ #Direction(s) of PBC for calculating electrostatics
PSOLVER PERIODIC ##ANALYTIC #The way to solve Poisson equation
&END POISSON
&SCF
MAX_SCF 20 #Maximum number of steps of inner SCF
EPS_SCF 1.0E-05 #Convergence threshold of density matrix of inner SCF
# SCF_GUESS RESTART #Use wavefunction from WFN_RESTART_FILE_NAME file
as initial guess
&OT
PRECONDITIONER FULL_SINGLE_INVERSE
MINIMIZER DIIS #CG is worth to consider in difficult cases
LINESEARCH 2PNT #1D line search algorithm for CG. 2PNT is default,
3PNT is better but more costly. GOLD is best but very expensive
&END OT
&OUTER_SCF
MAX_SCF 20 #Maximum number of steps of outer SCF
EPS_SCF 1.0E-05 #Convergence threshold of outer SCF
&END OUTER_SCF
&PRINT
&RESTART OFF #Do not generate wfn file to suppress meaningless I/O
cost
&END RESTART
&END PRINT
&END SCF
&PRINT
&MULLIKEN
FILENAME muliken
&EACH
MD 1
&END
PRINT_ALL F #If T, then printing full net AO and overlap population
matrix
&END MULLIKEN
&END PRINT
&END DFT
&END FORCE_EVAL
&MOTION
&MD
ENSEMBLE NVT
STEPS 250000 #Number of steps to run
TIMESTEP 1.0 #Step size in fs. Decrease it properly for high
temperature simulation
TEMPERATURE 5 #Initial and maintained temperature (K)
&THERMOSTAT
TYPE NOSE
&END THERMOSTAT
&END MD
&CONSTRAINT
&FIXED_ATOMS #Set atoms to be fixed
COMPONENTS_TO_FIX XYZ #Which fractional components will be fixed, can
be X, Y, Z, XY, XZ, YZ, XYZ
LIST 357..468
&END FIXED_ATOMS
&END CONSTRAINT
&PRINT
&TRAJECTORY
&EACH
MD 1 #Output frequency of coordinate
&END EACH
FORMAT xyz
&END TRAJECTORY
&RESTART
BACKUP_COPIES 0 #Maximum number of backing up restart file, 0 means
never
&EACH
MD 100 #Frequency of updating last restart file. Default is 20
&END EACH
&END RESTART
&RESTART_HISTORY
&EACH
MD 1000 #How many steps a history .restart file is generated.
Default is 500
&END EACH
&END RESTART_HISTORY
&END PRINT
&END MOTION
On Monday, February 26, 2024 at 5:07:59 PM UTC+8 Jürg Hutter wrote:
> Hi
>
> you are using a probably not tested combination of features.
> xTB with 2D periodicity and external electrical field (and hoping
> for the correct default Ewald setting) might not result in a
> correct setup. You should also use the PERIODIC_EFIELD option.
> I would suggest to simplify your system: use 3 D periodic cell with a large
> vacuum space (e.g. 80 A). This should correctly choose the Ewald settings
> and together with PERIODIC_EFIELD might work.
>
> regards
> JH
>
> ________________________________________
> From: cp... at googlegroups.com <cp... at googlegroups.com> on behalf of Evelyn
> Navarro <easa... at gmail.com>
> Sent: Friday, February 23, 2024 2:03 PM
> To: cp2k
> Subject: [CP2K:19964] Does the boundary setting affect the charge
> distribution under the electric field?
>
> Dear all
> I was studying the charge changes of two-dimensional piezoelectric
> materials under electric fields, and found that when the boundary is set as
> a period, the charge is actually concentrated in the middle of the
> material, which is not understandable. But if you use aperiodic boundaries,
> the charge will accumulate towards both ends of the material, which is
> normal. I tried the electric field and the periodic electric field
> respectively, and as long as the boundary is periodic, the charge will
> gather in the middle, which is incomprehensible, and I want to know why.
> What I want to study is periodic materials, and this periodic boundary is
> unavoidable.
>
> &GLOBAL
> PROJECT 468-zhouqi-0.004d-xybianjie-2024
> PRINT_LEVEL LOW
> RUN_TYPE MD
> &END GLOBAL
>
> &FORCE_EVAL
> METHOD Quickstep
> &SUBSYS
> &CELL
> ABC 38.9946780817 32.5196269485 20.000
> PERIODIC XY #Direction of applied PBC (geometry aspect)
> &END CELL
> &TOPOLOGY
> COORD_FILE_FORMAT XYZ
> COORD_FILE_NAME 468.xyz
> &CENTER_COORDINATES #Centering the atoms in the box
> &END
> &END
> # &VELOCITY #You can set initial atomic velocities in this section
> # &END VELOCITY
> &END SUBSYS
>
> &DFT
> # WFN_RESTART_FILE_NAME 400-RESTART.wfn
> CHARGE 0 #Net charge
> MULTIPLICITY 1 #Spin multiplicity
>
> &EFIELD
> INTENSITY 0.004
> POLARISATION -1.00000 0.00000 0.00000
> &END
>
> &QS
> EPS_DEFAULT 1E-10 #This is default. Set all EPS_xxx to values such that
> the energy will be correct up to this value
> EXTRAPOLATION ASPC #Extrapolation for wavefunction during e.g. MD. ASPC is
> default, PS also be used
> EXTRAPOLATION_ORDER 3 #Order for PS or ASPC extrapolation. 3 is default
> METHOD xTB
> &xTB
> CHECK_ATOMIC_CHARGES F #xTB calculation often crashes without setting this
> to false
> &PARAMETER
> DISPERSION_PARAMETER_FILE dftd3.dat
> PARAM_FILE_NAME xTB_parameters
> &END PARAMETER
> &END xTB
> &END QS
> &POISSON
> PERIODIC XY #Direction(s) of PBC for calculating electrostatics
> PSOLVER ANALYTIC #The way to solve Poisson equation
> &END POISSON
> &SCF
> MAX_SCF 20 #Maximum number of steps of inner SCF
> EPS_SCF 1.0E-05 #Convergence threshold of density matrix of inner SCF
> # SCF_GUESS RESTART #Use wavefunction from WFN_RESTART_FILE_NAME file as
> initial guess
> &OT
> PRECONDITIONER FULL_SINGLE_INVERSE
> MINIMIZER DIIS #CG is worth to consider in difficult cases
> LINESEARCH 2PNT #1D line search algorithm for CG. 2PNT is default, 3PNT is
> better but more costly. GOLD is best but very expensive
> &END OT
> &OUTER_SCF
> MAX_SCF 20 #Maximum number of steps of outer SCF
> EPS_SCF 1.0E-05 #Convergence threshold of outer SCF
> &END OUTER_SCF
> &PRINT
> &RESTART OFF #Do not generate wfn file to suppress meaningless I/O cost
> &END RESTART
> &END PRINT
> &END SCF
> &END DFT
> &END FORCE_EVAL
>
> &MOTION
> &MD
> ENSEMBLE NVT
> STEPS 250000 #Number of steps to run
> TIMESTEP 1.0 #Step size in fs. Decrease it properly for high temperature
> simulation
> TEMPERATURE 5 #Initial and maintained temperature (K)
> &THERMOSTAT
> TYPE NOSE
> &END THERMOSTAT
> &END MD
> &CONSTRAINT
> &FIXED_ATOMS #Set atoms to be fixed
> COMPONENTS_TO_FIX XYZ #Which fractional components will be fixed, can be
> X, Y, Z, XY, XZ, YZ, XYZ
> LIST 357..468
>
> &END FIXED_ATOMS
> &END CONSTRAINT
> &PRINT
> &TRAJECTORY
> &EACH
> MD 1 #Output frequency of coordinate
> &END EACH
> FORMAT xyz
> &END TRAJECTORY
> &RESTART
> BACKUP_COPIES 0 #Maximum number of backing up restart file, 0 means never
> &EACH
> MD 100 #Frequency of updating last restart file. Default is 20
> &END EACH
> &END RESTART
> &RESTART_HISTORY
> &EACH
> MD 1000 #How many steps a history .restart file is generated. Default is
> 500
> &END EACH
> &END RESTART_HISTORY
> &END PRINT
> &END MOTION
>
> Thanks
> Evelyn Navarro
>
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