Based on the three VASP wiki examples in the links 1, 2 and 3
Task: Perform a relaxation of the first two layers of a Ni (100) surface, thereafter calculate its DOS and bandstructure.
First, copy the example folder which contains some of the VASP input files
cp -r /software/sse/manual/vasp/training/ws2020/Ni100_surf .
cd Ni100_surf
and copy the latest POTCAR file for Ni
cp /software/sse/manual/vasp/POTCARs/PBE/2015-09-21/Ni/POTCAR .
POSCAR
fcc (100) surface
3.53
.50000 .50000 .00000
-.50000 .50000 .00000
.00000 .00000 5.00000
Ni
5
Selective Dynamics
Cartesian
.00000 .00000 .00000 F F F
.00000 .50000 .50000 F F F
.00000 .00000 1.00000 F F F
.00000 .50000 1.50000 T T T
.00000 .00000 2.00000 T T T
INCAR
ISTART = 0; ICHARG = 2
general:
SYSTEM = clean Ni(100) surface
ENCUT = 270
ISMEAR = 2 ; SIGMA = 0.2
ALGO = Fast
EDIFF = 1E-6
spin:
ISPIN=2
MAGMOM = 5*1
dynamic:
NSW = 100
POTIM = 0.8
IBRION = 1
KPOINTS
k-points
0
Monkhorst-Pack
9 9 1
0 0 0
First, note how selective dynamics (S) works in the POSCAR file
Selective Dynamics
Cartesian
.00000 .00000 .00000 F F F
.00000 .50000 .50000 F F F
.00000 .00000 1.00000 F F F
.00000 .50000 1.50000 T T T
.00000 .00000 2.00000 T T T
So, for relaxation F=False
and T=True
, so one sees that the two atoms at z=1.5 and 2.0 are able to move in all directions, while the three lower atoms (layers) are fixed.
Run the calculation with
sbatch run.sh
and observe the relaxation e.g. with
cat OSZICAR
After the calculation is finished, compare the forces in OUTCAR between the first and the last step.
First step:
POSITION TOTAL-FORCE (eV/Angst)
-----------------------------------------------------------------------------------
0.00000 0.00000 0.00000 0.000000 0.000000 0.419201
0.00000 1.76500 1.76500 0.000000 0.000000 -0.401608
0.00000 0.00000 3.53000 0.000000 0.000000 -0.002589
0.00000 1.76500 5.29500 0.000000 0.000000 0.392849
0.00000 0.00000 7.06000 -0.000000 -0.000000 -0.407852
-----------------------------------------------------------------------------------
total drift: -0.000000 -0.000000 -0.008050
Last step:
POSITION TOTAL-FORCE (eV/Angst)
-----------------------------------------------------------------------------------
0.00000 0.00000 0.00000 -0.000000 0.000000 0.425910
0.00000 1.76500 1.76500 0.000000 -0.000000 -0.402950
0.00000 0.00000 3.53000 -0.000000 0.000000 -0.023012
0.00000 1.76500 5.29871 -0.000000 0.000000 -0.001056
-0.00000 -0.00000 6.98070 -0.000000 -0.000000 0.001107
-----------------------------------------------------------------------------------
total drift: 0.000000 -0.000000 -0.019988
Check the obtained relaxed structure in CONTCAR
:
fcc (100) surface
3.53000000000000
0.5000000000000000 0.5000000000000000 0.0000000000000000
-0.5000000000000000 0.5000000000000000 0.0000000000000000
0.0000000000000000 0.0000000000000000 5.0000000000000000
Ni
5
Selective dynamics
Direct
0.0000000000000000 0.0000000000000000 0.0000000000000000 F F F
0.5000000000000000 0.5000000000000000 0.1000000000000014 F F F
0.0000000000000000 0.0000000000000000 0.2000000000000028 F F F
0.5000000000000000 0.5000000000000000 0.3002099841022341 T T T
-0.0000000000000000 0.0000000000000000 0.3955072458335201 T T T
Now, in a new folder “dos”, calculate the local DOS for the relaxed Ni(100) surface using CONTCAR from the previous step
mkdir dos
cp CONTCAR dos/POSCAR
cp INCAR.dos dos/INCAR
cp POTCAR KPOINTS run.sh dos
cd dos
Also note that we use a new INCAR (from INCAR.dos) which looks like
general:
SYSTEM = clean (100) Ni surface
ENMAX = 270
ISMEAR = -5
ALGO = Normal
spin:
ISPIN = 2
MAGMOM = 5*1
LORBIT = 11 # lm and site decomposed DOS inside PAW spheres
Run the calculation with
sbatch run.sh
After it finishes, at the end of OUTCAR, check the information on local charge and magnetization
total charge
# of ion s p d tot
------------------------------------------
1 0.464 0.328 8.294 9.086
2 0.488 0.483 8.309 9.280
3 0.491 0.485 8.317 9.294
4 0.498 0.505 8.334 9.338
5 0.477 0.350 8.332 9.158
--------------------------------------------------
tot 2.418 2.151 41.586 46.156
magnetization (x)
# of ion s p d tot
------------------------------------------
1 -0.003 -0.021 0.751 0.727
2 -0.008 -0.026 0.645 0.611
3 -0.008 -0.026 0.636 0.602
4 -0.008 -0.026 0.630 0.596
5 -0.004 -0.021 0.725 0.700
--------------------------------------------------
tot -0.032 -0.120 3.388 3.236
Now, calculate the corresponding bandstructure for the relaxed Ni(100) surface structure. Go to the main folder “Ni100_surf” and there create the folder “band” and copy the needed files
mkdir band
cp CONTCAR band/POSCAR
cp INCAR.band band/INCAR
cp KPOINTS.band band/KPOINTS
cp POTCAR run.sh band
cd band
Also note that we use a new INCAR (from INCAR.band) which looks like
ICHARG = 11
general:
SYSTEM = clean (100) nickel surface
ENMAX = 270
ISMEAR = 2 ; SIGMA = 0.2
ALGO = Normal
spin:
ISPIN = 2
MAGMOM = 5*1
LORBIT = 11
Copy CHGCAR
cp ../dos/CHGCAR .
This time KPOINTS for the bandstructure looks like
kpoints for band-structure G-X-M-G
13
reziprok
.00000 .00000 .00000 1
.12500 .00000 .00000 1
.25000 .00000 .00000 1
.37500 .00000 .00000 1
.50000 .00000 .00000 1
.50000 .12500 .00000 1
.50000 .25000 .00000 1
.50000 .37500 .00000 1
.50000 .50000 .00000 1
.37500 .37500 .00000 1
.25000 .25000 .00000 1
.12500 .12500 .00000 1
.00000 .00000 .00000 1
Submit the job
sbatch run.sh
and wait for it to finish. Investigate the bandstructure using p4vasp, compare with the VASP wiki example.
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