From Web Elements for Ni, the atomization energy was determined:
Hi Stephen
For the description of metallic bulk systems, you will need Brillouin zone sampling with an appropriate k point mesh. It seems this is missing in your input.
HTH
Matthias
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Hi Stephen
For bulk Cu you will need to apply
- k point sampling (e.g. MP 8 8 8)
- diagonalization (with Broyden mixing)
- smearing (e.g. T(elec) = 2000 K)
Moreover, you should use the conventional (cubic) unit cell with 4 Cu atoms instead of the primitive one with one Cu atom. CP2K is slower for non-orthorhombic cells.
Plane wave (PW) codes are fast for small unit cells as they scale with the size of the cell which has to be filled with PWs. That’s not the case for CP2K using atomic basis functions which requires to calculate the interactions with the image Cu atoms in neighboring cells. So it can make sense to use multiple unit cells, e.g. a 2x2x2 supercell, and to reduce the k point mesh correspondingly (e.g. from 8x8x8 to 4x4x4).
Below you will find a CP2K input for bulk Cu in which I have considered the suggestions above. No guarantee, of course, that it will work properly.
Matthias
&GLOBAL
PRINT_LEVEL low
PROJECT_NAME Cu
RUN_TYPE cell_opt
&END GLOBAL
&MOTION
&CELL_OPT
EXTERNAL_PRESSURE [bar] 1.0
MAX_DR 0.001
MAX_FORCE 0.0001
MAX_ITER 400
OPTIMIZER BFGS
PRESSURE_TOLERANCE [bar] 10.0
RMS_DR 0.0003
RMS_FORCE 0.00003
TYPE direct_cell_opt
&BFGS
TRUST_RADIUS 0.1
USE_MODEL_HESSIAN off
USE_RAT_FUN_OPT on
&END BFGS
&END CELL_OPT
&END MOTION
&FORCE_EVAL
METHOD QS
STRESS_TENSOR analytical
&DFT
BASIS_SET_FILE_NAME BASIS_MOLOPT
POTENTIAL_FILE_NAME GTH_POTENTIALS
&KPOINTS
SCHEME MONKHORST-PACK 2 2 2
FULL_GRID yes
SYMMETRY yes
VERBOSE yes
PARALLEL_GROUP_SIZE -1
&END KPOINTS
&MGRID
NGRIDS 5
CUTOFF 400.0
REL_CUTOFF 60.0
&END MGRID
&QS
EPS_DEFAULT 1.0E-12
EXTRAPOLATION use_prev_p
&END QS
&SCF
ADDED_MOS 60
EPS_SCF 1.0E-8
MAX_SCF 300
SCF_GUESS restart
&DIAGONALIZATION yes
ALGORITHM STANDARD
&END DIAGONALIZATION
&MIXING yes
ALPHA 0.4
BETA 1.0
METHOD broyden_mixing
NBROYDEN 8
&END MIXING
&SMEAR on
METHOD FERMI_DIRAC
ELECTRONIC_TEMPERATURE [K] 2000.0
&END SMEAR
&END SCF
&XC
&XC_FUNCTIONAL PBE
&END XC_FUNCTIONAL
&VDW_POTENTIAL
POTENTIAL_TYPE pair_potential
&PAIR_POTENTIAL
TYPE DFTD3(BJ)
PARAMETER_FILE_NAME dftd3.dat
REFERENCE_FUNCTIONAL PBE
&END PAIR_POTENTIAL
&END VDW_POTENTIAL
&END XC
&END DFT
&SUBSYS
&CELL
ABC 3.62 3.62 3.62
MULTIPLE_UNIT_CELL 2 2 2
&END CELL
&COORD
SCALED
Cu 0 0 0
Cu 0 1/2 1/2
Cu 1/2 0 1/2
Cu 1/2 1/2 0
&END COORD
&KIND Cu
BASIS_SET DZVP-MOLOPT-SR-GTH-q11
POTENTIAL GTH-PBE-q11
&END KIND
&TOPOLOGY
MULTIPLE_UNIT_CELL 2 2 2
&END TOPOLOGY
&END SUBSYS
&END FORCE_EVAL
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Hi Brendan
That should be the same, since the MULTIPLE_UNIT_CELL keyword just replicates the unit cell internally and the atomic coordinates printed by CP2K are for the supercell. This keyword facilitates the input of supercells. CP2K can also be used in this way to create supercells, though this might be easier with other tools.
Best regards
Matthias
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Hi Stephen
Such a set up should work for bulk metal systems in general. Just check the convergence of the results with respect to the k point mesh size. You can reduce the mixing parameter ALPHA if convergence problems occur.
Best regards
Matthias
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