[Wien] Fe slab
Peter Blaha
pblaha at theochem.tuwien.ac.at
Fri Jul 4 14:56:26 CEST 2008
Why would you use such a struct file ?
a) With limited experience, start with small models, 5 or 7 layers only.
b) I don't know how this struct file was created, but for sure a 15
layer Fe(001) slab can have inversion symmetry and I'm pretty sure that
WIEN should be able to find the proper symmetry (sgroup) when you allow
for it. Remove ALL numbering for atomes (Fe1,2,3,...) and run the
initialization. sgroup (or nn in most cases) should always group 2 atoms
together (make them equivalent, except the center). sgroup should also
shift the atoms along z.
Your calculations will be 4 times faster when you have inversion symmetry!
c) When going for thicker slabs, you should also improve your vacuum. It
does not make sense to go to a thick slab, but have surface-surface
interactions through the vacuum.
d) k-mesh: why would one use a "2" fold k-mesh in z-direction. With
recent WIEN2k versions you can also specify a 21x21x1 mesh for kgen.
e) Some cases may need more than 40 iterations. As long as it does not
diverge, just continue.
f) Eventually TEMP with some broadening (0.005) may help convergence.
However, in particular with magnetic systems, make sure that the
broadening does not influence your magnetism and recheck with smaller
broadening.
Lukasz Plucinski schrieb:
> I am trying to do spin-polarized slab calculation on Fe(001). It runs
> ok, but does not converge (fluctuates) after 40 iterations. I tried with
> up 1000 k-points (21x21x2 - I guess its already too much), 0.05 mixing
> factor, and both PBE(96) and W-C(06) GGAs. Other settings default,
> spin-polarized calculation right away.
>
> Which parameters should I try to change next ?
>
> Struct file below.
>
> Lukasz
>
>
>
> Fe-slab-001
>
> P LATTICE,NONEQUIV.ATOMS:
> 15
> MODE OF CALC=RELA
> unit=ang
> 5.416902 5.416902 54.169021 90.000000 90.000000
> 90.000000
> ATOM -1: X=0.00000000 Y=0.00000000 Z=0.10000000
> MULT= 1 ISPLIT=-2
> Fe1 NPT= 781 R0=0.00010000 RMT= 2.3450 Z:
> 26.0
> LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000
> 0.0000000 1.0000000 0.0000000
> 0.0000000 0.0000000 1.0000000
> ATOM -2: X=0.50000000 Y=0.50000000 Z=0.15000000
> MULT= 1 ISPLIT=-2
> Fe2 NPT= 781 R0=0.00010000 RMT= 2.3450 Z:
> 26.0
> LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000
> 0.0000000 1.0000000 0.0000000
> 0.0000000 0.0000000 1.0000000
> ATOM -3: X=0.00000000 Y=0.00000000 Z=0.20000000
> MULT= 1 ISPLIT=-2
> Fe3 NPT= 781 R0=0.00010000 RMT= 2.3450 Z:
> 26.0
> LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000
> 0.0000000 1.0000000 0.0000000
> 0.0000000 0.0000000 1.0000000
> ATOM -4: X=0.50000000 Y=0.50000000 Z=0.25000000
> MULT= 1 ISPLIT=-2
> Fe4 NPT= 781 R0=0.00010000 RMT= 2.3450 Z:
> 26.0
> LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000
> 0.0000000 1.0000000 0.0000000
> 0.0000000 0.0000000 1.0000000
> ATOM -5: X=0.00000000 Y=0.00000000 Z=0.30000000
> MULT= 1 ISPLIT=-2
> Fe5 NPT= 781 R0=0.00010000 RMT= 2.3450 Z:
> 26.0
> LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000
> 0.0000000 1.0000000 0.0000000
> 0.0000000 0.0000000 1.0000000
> ATOM -6: X=0.50000000 Y=0.50000000 Z=0.35000000
> MULT= 1 ISPLIT=-2
> Fe6 NPT= 781 R0=0.00010000 RMT= 2.3450 Z:
> 26.0
> LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000
> 0.0000000 1.0000000 0.0000000
> 0.0000000 0.0000000 1.0000000
> ATOM -7: X=0.00000000 Y=0.00000000 Z=0.40000000
> MULT= 1 ISPLIT=-2
> Fe7 NPT= 781 R0=0.00010000 RMT= 2.3450 Z:
> 26.0
> LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000
> 0.0000000 1.0000000 0.0000000
> 0.0000000 0.0000000 1.0000000
> ATOM -8: X=0.50000000 Y=0.50000000 Z=0.45000000
> MULT= 1 ISPLIT=-2
> Fe8 NPT= 781 R0=0.00010000 RMT= 2.3450 Z:
> 26.0
> LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000
> 0.0000000 1.0000000 0.0000000
> 0.0000000 0.0000000 1.0000000
> ATOM -9: X=0.00000000 Y=0.00000000 Z=0.50000000
> MULT= 1 ISPLIT=-2
> Fe9 NPT= 781 R0=0.00010000 RMT= 2.3450 Z:
> 26.0
> LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000
> 0.0000000 1.0000000 0.0000000
> 0.0000000 0.0000000 1.0000000
> ATOM -10: X=0.50000000 Y=0.50000000 Z=0.55000000
> MULT= 1 ISPLIT=-2
> Fe10 NPT= 781 R0=0.00010000 RMT= 2.3450 Z:
> 26.0
> LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000
> 0.0000000 1.0000000 0.0000000
> 0.0000000 0.0000000 1.0000000
> ATOM -11: X=0.00000000 Y=0.00000000 Z=0.60000000
> MULT= 1 ISPLIT=-2
> Fe11 NPT= 781 R0=0.00010000 RMT= 2.3450 Z:
> 26.0
> LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000
> 0.0000000 1.0000000 0.0000000
> 0.0000000 0.0000000 1.0000000
> ATOM -12: X=0.50000000 Y=0.50000000 Z=0.65000000
> MULT= 1 ISPLIT=-2
> Fe12 NPT= 781 R0=0.00010000 RMT= 2.3450 Z:
> 26.0
> LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000
> 0.0000000 1.0000000 0.0000000
> 0.0000000 0.0000000 1.0000000
> ATOM -13: X=0.00000000 Y=0.00000000 Z=0.70000000
> MULT= 1 ISPLIT=-2
> Fe13 NPT= 781 R0=0.00010000 RMT= 2.3450 Z:
> 26.0
> LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000
> 0.0000000 1.0000000 0.0000000
> 0.0000000 0.0000000 1.0000000
> ATOM -14: X=0.50000000 Y=0.50000000 Z=0.75000000
> MULT= 1 ISPLIT=-2
> Fe14 NPT= 781 R0=0.00010000 RMT= 2.3450 Z:
> 26.0
> LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000
> 0.0000000 1.0000000 0.0000000
> 0.0000000 0.0000000 1.0000000
> ATOM -15: X=0.00000000 Y=0.00000000 Z=0.80000000
> MULT= 1 ISPLIT=-2
> Fe15 NPT= 781 R0=0.00010000 RMT= 2.3450 Z:
> 26.0
> LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000
> 0.0000000 1.0000000 0.0000000
> 0.0000000 0.0000000 1.0000000
> 8 NUMBER OF SYMMETRY OPERATIONS
> -1 0 0 0.0000000
> 0-1 0 0.0000000
> 0 0 1 0.0000000
> 1
> -1 0 0 0.0000000
> 0 1 0 0.0000000
> 0 0 1 0.0000000
> 2
> 0-1 0 0.0000000
> -1 0 0 0.0000000
> 0 0 1 0.0000000
> 3
> 0 1 0 0.0000000
> -1 0 0 0.0000000
> 0 0 1 0.0000000
> 4
> 0-1 0 0.0000000
> 1 0 0 0.0000000
> 0 0 1 0.0000000
> 5
> 0 1 0 0.0000000
> 1 0 0 0.0000000
> 0 0 1 0.0000000
> 6
> 1 0 0 0.0000000
> 0-1 0 0.0000000
> 0 0 1 0.0000000
> 7
> 1 0 0 0.0000000
> 0 1 0 0.0000000
> 0 0 1 0.0000000
> 8
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--
-----------------------------------------
Peter Blaha
Inst. Materials Chemistry, TU Vienna
Getreidemarkt 9, A-1060 Vienna, Austria
Tel: +43-1-5880115671
Fax: +43-1-5880115698
email: pblaha at theochem.tuwien.ac.at
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