[Wien] Rutile structure and antiferromagnetic calculation
Pablo de la Mora
pm at hp.fciencias.unam.mx
Fri Nov 4 14:16:55 CET 2011
Thank for your suggestions.
Yes, as you suggests I could work with the rutile structure.
I did not know how to automatically split the oxygen atoms in this
structure without changeing to Cmmm structure.
Now I found that 'nn' does it, while 'sgroup' splits the O atoms and
changes the structure to Cmmm at the same time.
I used the new afmimput and it does not seem to work
I tried in the antiferromagnetic 'rutile'.struct:
a a c, 90 90 90
Cr1 0 0 0
Cr2 .5 .5 .5
O1 b b 0
-b -b 0
O2 .5+b .5-b .5
.5-b .5+b .5
with b~0.3
Title
7.558908 7.558908 5.669181 90.000000 90.000000 90.000000
Cr1 -4: X=0.00000000 Y=0.00000000 Z=0.00000000
O1 -3: X=0.30000000 Y=0.30000000 Z=0.00000000
-3: X=0.70000000 Y=0.70000000 Z=0.00000000
O2 -2: X=0.80000000 Y=0.20000000 Z=0.50000000
-2: X=0.20000000 Y=0.80000000 Z=0.50000000
Cr2 -1: X=0.50000000 Y=0.50000000 Z=0.50000000
8 NUMBER OF SYMMETRY OPERATIONS
(obviously modified *.struct to show the atomic positions, and I
reordered the atoms)
with:
14
1 0 0 0.50000000
0 -1 0 0.50000000
0 0 1 0.50000000
I also tried with the Cmmm structure.
El 31/10/11 02:59, Peter Blaha escribió:
> First: the automatic mode using case.struct_supergroup will not work
> if you
> change the lattice type.
> Although sgroup suggests the new spacegroup Cmmm, there is actually no
> need to
> follow this advise, but you can do the initialization also in the
> original
> P lattice and use the standard rutile struct file as supergroup file.
>
> Secondly, this is a case with a non-unity "local-rotation-matrix" and
> I suspected
> for some time that there is a problem. I guess, the code should simply
> neglect the rotloc and testing this in your example seems to work.
>
> I attach a modified afminput.f routine, where I set rotloc to the
> identity.
> Please verify, that runafm and runsp give the same results!
>
> Regards
>
> Am 28.10.2011 22:09, schrieb Pablo de la Mora:
>> I have tried an antiferromagnetic calculation on the rutile structure
>> and it does not seem to work:
>> the structure is:
>> (CrO2 is not antiferromagnetic, and the parameters I use are not
>> precise, I erased some lines)
>>
>> Title
>> CXY LATTICE,NONEQUIV.ATOMS: 4 65 Cmmm
>> MODE OF CALC=RELA unit=ang
>> 10.689910 10.689910 5.669181 90.000000 90.000000 90.000000
>> ATOM 1: X=0.00000000 Y=0.00000000 Z=0.00000000
>> MULT= 1 ISPLIT= 8
>> Cr1 NPT= 781 R0=0.00005000 RMT= 1.69 Z: 24.0
>> ----------------
>> ATOM 2: X=0.00000000 Y=0.30000000 Z=0.00000000
>> MULT= 2 ISPLIT= 8
>> 2: X=0.00000000 Y=0.70000000 Z=0.00000000
>> O 1 NPT= 781 R0=0.00010000 RMT= 1.50 Z: 8.0
>> ---------------------------------
>> ATOM 3: X=0.20000000 Y=0.00000000 Z=0.50000000
>> MULT= 2 ISPLIT= 8
>> 3: X=0.80000000 Y=0.00000000 Z=0.50000000
>> O 2 NPT= 781 R0=0.00010000 RMT= 1.50 Z: 8.0
>> ----------------------------
>> ATOM 4: X=0.00000000 Y=0.50000000 Z=0.50000000
>> MULT= 1 ISPLIT= 0
>> Cr2 NPT= 781 R0=0.00005000 RMT= 1.69 Z: 24.0
>> ----------------------------------
>> 8 NUMBER OF SYMMETRY OPERATIONS
>>
>> Then I join Cr1 and Cr2, O1 and O2 and put Cxy (to keep the same
>> crystal structure but with no antiferromagnetic order):
>>
>> Title
>> CXY LATTICE,NONEQUIV.ATOMS: 2
>> MODE OF CALC=RELA unit=ang
>> 10.689910 10.689910 5.669181 90.000000 90.000000 90.000000
>> ATOM -1: X=0.00000000 Y=0.00000000 Z=0.00000000
>> MULT= 2 ISPLIT= 8
>> -1: X=0.00000000 Y=0.50000000 Z=0.50000000
>> Cr NPT= 781 R0=0.00005000 RMT= 1.69 Z: 24.0
>> ------------------
>> ATOM -2: X=0.00000000 Y=0.30000000 Z=0.00000000
>> MULT= 4 ISPLIT= 8
>> -2: X=0.00000000 Y=0.70000000 Z=0.00000000
>> -2: X=0.20000000 Y=0.00000000 Z=0.50000000
>> -2: X=0.80000000 Y=0.00000000 Z=0.50000000
>> O NPT= 781 R0=0.00010000 RMT= 1.50 Z: 8.0
>> ------------------
>> 16 NUMBER OF SYMMETRY OPERATIONS
>> -------------------
>> 12
>> 0 1 0 0.00000000
>> 1 0 0 0.50000000
>> 0 0 1 0.50000000
>> ---------------------------
>>
>> I try this operation #12 and I get a blank
>>
>> '<>.inclmcopy'
>>
>> In other antiferromagnetic systems it seems to work.
>>
>>
>>
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>
>
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