Based on the VASP wiki example in this link
Task: For spin-polarized (collinear magnetism) fcc Ni. Do a lattice parameter optimization, calculate DOS and bandstructure.
First, copy the example folder which contains some of the VASP input files
cp -r /software/sse/manual/vasp/training/ws2020/fcc_Ni .
cd fcc_Ni
and copy the latest POTCAR file for Ni
cp /software/sse/manual/vasp/POTCARs/PBE/2015-09-21/Ni/POTCAR .
Perform the calculations below in the same way as was done for the cd Si example.
POSCAR
fcc Ni
3.53
0.5 0.5 0.0
0.0 0.5 0.5
0.5 0.0 0.5
Ni
1
cartesian
0 0 0
INCAR
general:
SYSTEM = fcc Ni
ISTART = 0 ; ICHARG=2
ENCUT = 270
ISMEAR = 1 ; SIGMA = 0.2
LORBIT=11
spin:
ISPIN=2
MAGMOM = 1
KPOINTS
k-points
0
Monkhorst Pack
11 11 11
0 0 0
Similar as for the cd Si example, check the total energy over a range of volumes, by using the tailored job script “run-vol.sh”
sbatch run-vol.sh
after it finishes, check the total energy vs lattice constant e.g. using gnuplot
gnuplot
and at the prompt type
plot "SUMMARY.dia" using ($1):($4) w lp
is the equilibrium lattice parameter close to a = 3.5 Å?
In the same way as was done in fcc Si and cd Si, investigate the output from Birch-Murnaghan EOS by using the “eqos.py” script.
Create a new folder “dos”, copy the relevant files and go there
mkdir dos
cp INCAR POSCAR KPOINTS POTCAR run.sh dos
cd dos
As in the previous example for cd Si we compute DOS in a single step. Edit INCAR such that it looks like
general:
SYSTEM = fcc Ni
ISTART = 0 ; ICHARG=2
ENCUT = 270
ISMEAR = -5
LORBIT=11
spin:
ISPIN=2
MAGMOM = 1
notice the change to ISMEAR=-5, the tetrahedron method with Blöchl corrections, suitable for DOS and total energies.
Finally, submit the job
sbatch run.sh
To check the result after finish, use p4vasp
as in the previous examples.
In the main “fcc_Ni” folder, create a new folder “band”, copy the relevant files and go there, note the treatment for the “KPOINTS” file
mkdir band
cp INCAR POSCAR POTCAR run.sh band
cp KPOINTS.band band/KPOINTS
cd band
the file KPOINTS.band, which was copied to KPOINTS, looks like
kpoints for bandstructure L-G-X-U K-G
10
line
reciprocal
0.50000 0.50000 0.50000 1
0.00000 0.00000 0.00000 1
0.00000 0.00000 0.00000 1
0.00000 0.50000 0.50000 1
0.00000 0.50000 0.50000 1
0.25000 0.62500 0.62500 1
0.37500 0.7500 0.37500 1
0.00000 0.00000 0.00000 1
As in previous bandstructure examples, e.g. cd Si, we need a suitable CHGCAR
file. First check that INCAR is correct, edit the file using e.g. gedit
such that
ICHARG=11
i.e. that CHGCAR is read. Copy CHGCAR from the previous DOS calculation
cp ../dos/CHGCAR .
thereafter submit the job
sbatch run.sh
To check the results after finish, use p4vasp
. Compare with the result on the VASP wiki.
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