[Wien] Problem with DOS for Fe-Pd system
Peter Blaha
pblaha at theochem.tuwien.ac.at
Wed Apr 28 10:34:46 CEST 2010
Your k-mesh is wrong.
All 4 k-points are "the same" and thus of course the eigenvalues are identical.
> K= 0.25000 0.25000 0.25000 1
> K= 0.25000 0.25000 0.75000 2
You have a simple cubic lattice with inversion, rotations and "mirror planes".
Hence you can subtract (0,0,1) from the second k-point and after mirroring z
you come to the coordinates of the first k-point.
Make sure you case.struct file is correct and contains the correct symmetry operations, and
no warnings in case.outputs. You should still have 48 operations! Rerun x kgen.
with 24 k-points as input it gives only 1 (shifted) k-point.
Maxim Rakitin schrieb:
> Dear Prof. Blaha,
>
> Please see my answers on your questions below:
>
> PB> Check case.output1up*. Are the eigenvalues the same ?
> MR> I checked case.output1up_1 file. There are 4 blocks of eigenvalues,
> and all values are different. Please see the file in attached archive
> for further analysis.
>
> PB> Do they agree with the eigenvalues listed in case.qtlup ?
> MR> Yes, I compared eigenvalues for the 1st k-point with ones in
> case.qtlup file. I hope this is right for other 3 k-points.
>
> PB> Do the k-points agree with case.klist ?
> MR> Yes, they do agree. I have the following in case.output1up_1:
> K= 0.25000 0.25000 0.25000 1
> K= 0.25000 0.25000 0.75000 2
> K= 0.25000 0.75000 0.25000 3
> K= 0.25000 0.75000 0.75000 4
> and case.klist file contains the following:
> 1 1 1 1 4 2.0 -7.0 1.5
> 24 k, div: ( 2 2 2)
> 2 1 1 3 4 2.0
> 3 1 3 1 4 2.0
> 4 1 3 3 4 2.0
> END
>
> PB> Check case.klist: do you have 4 times the same k-point ?
> MR> No. As you can see in my previous answer, all 4 k-points are unique.
>
> Also please answer my questions in my previous mail.
>
> Thanks a lot.
>
> P.S. I've started this calculation with 64 k-points, maybe this can fix
> the problem. What do you think about it?
>
> Best regards,
> Maxim Rakitin
> South Ural State University,
> 76 Lenin av., Chelyabinsk, Russia, 454080
> Email:rms85 at mail.ru
> Web:http://www.susu.ac.ru
>
>
> 22.04.2010 13:36, Maxim Rakitin пишет:
>> Dear Prof. Blaha,
>>
>> Thank you for your review. I'll check the files you mentioned and let
>> you know the result.
>>
>> One thing I'd like to note: I use 24 k-points with inversion, so there
>> are only 4 irreducible k-points. Does it mean that my system is
>> equivalent to bcc-Fe (1 atom) calculation with 54*24 k-points?
>>
>> And one question: what should I do to resolve the problem? Do I need
>> to increase size of k-mesh only?
>>
>> Thanks.
>>
>> Best regards,
>> Maxim Rakitin
>> South Ural State University,
>> Chelyabinsk, Russia
>> email: rms85 at physics.susu.ac.ru
>> web: http://www.susu.ac.ru
>>
>> 22.04.2010 13:09, Peter Blaha пишет:
>>> I checked the qtl file you sent.
>>>
>>> You do not have any "band-dispersion", i.e. all 4 k-points in the
>>> file have
>>> identical energies. E.g.:
>>>
>>> ...
>>> BAND: 236
>>> 0.48370 1 0.03555 0.00938 0.00117 0.02500 0.00000 0.02500 0.00000
>>> ...
>>> 0.48370 54 0.00586 0.00349 0.00000 0.00237 0.00000 0.00237 0.00000
>>> 0.48370 55 0.49372
>>> 0.48370 1 0.03555 0.00938 0.00117 0.02500 0.00000 0.02500 0.00000
>>> 0.48370 2 0.00891 0.00049 0.00021 0.00820 0.00448 0.00372 0.00000
>>> ...
>>> 0.48370 54 0.01267 0.00048 0.00028 0.01191 0.00244 0.00947 0.00000
>>> 0.48370 55 0.49372
>>> 0.48370 1 0.03555 0.00938 0.00117 0.02500 0.00000 0.02500 0.00000
>>> 0.48370 2 0.00892 0.00049 0.00021 0.00821 0.00448 0.00373 0.00000
>>> ...
>>> 0.48370 54 0.01267 0.00048 0.00028 0.01191 0.00244 0.00947 0.00000
>>> 0.48370 55 0.49372
>>> 0.48370 1 0.03555 0.00938 0.00117 0.02500 0.00000 0.02500 0.00000
>>> 0.48370 2 0.00892 0.00049 0.00021 0.00821 0.00448 0.00373 0.00000
>>> ...
>>>
>>> When all k-pints have identical energies, the DOS consists of
>>> "delta-peaks" at
>>> those energies and since your DOS energy-mesh usually does not
>>> coincide with any of those
>>> eigenvalues, you find only zero DOS. (You can see in case.outputt
>>> that the integrated DOS
>>> properly increases whenever an eigenvalue was covered).
>>>
>>> Check case.output1up*. Are the eigenvalues the same ? Do they agree
>>> with the
>>> eigenvalues listed in case.qtlup ? Do the k-points agree with
>>> case.klist ?
>>> Check case.klist: do you have 4 times the same k-point ?
>>>
>>> In any case. the DOS will be crude. You are using a 3x3x3 supercell,
>>> but probably have
>>> only a 2x2x2 k-mesh. This is equivalent to a bcc-Fe calculation with
>>> only 6x6x6 k-points,
>>> which is certainly not sufficient.
>>>
>>> PS: Next WIEW2k release will have an option to get a DOS with just
>>> ONE k-point using
>>> a broadening scheme. But be aware of the fact, that this DOS could be
>>> "lousy" unless
>>> you have really large cells and depends a lot on the broadening
>>> parameters.
>>>
>>> Maxim Rakitin schrieb:
>>>> Dear WIEN2k users,
>>>>
>>>> I have a problem with DOS for Fe-Pd system. Namely, I got null
>>>> values for all tot, s, p, d, d-eg, d-t2g, f orbitals, and it seems
>>>> very strange for me. Calculations of pure Fe gave me correct DOS
>>>> states. Moreover, I got reasonable results of DOS for Fe-H-Pd system.
>>>>
>>>> I performed spin-polarized calculation of Fe53Pd bcc system (see
>>>> attached Fe53Pd.struct file (after minimization)). I used GGA-PBE96
>>>> XC potential., RKmax=8.75, size of k-mesh was 24 (4 irreducible
>>>> k-points). SCF cycle was started by the following command: *min -j
>>>> "runsp_lapw -p -I -ec 0.0001 -cc 0.001 -fc 1.0 -i 200"*, after it
>>>> minimization completed successfully. Then I ran the following
>>>> commands to generate *.qtl* files: *x lapw2 -p -c -qtl -up* and *x
>>>> lapw2 -p -c -qtl -dn*, created Fe53Pd.int file (see in attachment)
>>>> and ran *x tetra -c -up/-dn*. After it I got Fe53Pd.dosXup/dn files
>>>> with 0.00000000 values for all states. I don't know where the
>>>> problem came from, maybe I don't have proper *.vector* files in
>>>> $SCRATCH directory. I've already tried to rerun *x lapw1 -p -c
>>>> -up/-dn* and then *x lapw2 -p -c -qtl -up/-dn*, but the result was
>>>> the same.
>>>>
>>>> Could anyone suggest me what to do to get correct DOS? Do I need to
>>>> provide any other input/output file? Any help will be really
>>>> appreciated. Thanks in advance.
>>>> *_
>>>> Environment:_*
>>>> *WIEN2k version:* WIEN2k_08.3 (Release 18/9/2008)
>>>> *Machine type:* cluster with Infiniband interconnect and Torque
>>>> batch system
>>>> *OS type:* Linux version 2.6.16.54-0.2.5-smp (geeko at buildhost) (gcc
>>>> version 4.1.2 20070115 (prerelease) (SUSE Linux)) #1 SMP Mon Jan 21
>>>> 13:29:51 UTC 2008
>>>> *Fortran compiler:* 10.1.015
>>>> *MKL libraries:* 10.0.3.020 (em64t)
>>>>
>>>> --
>>>> Best regards,
>>>> Maxim Rakitin
>>>> South Ural State University,
>>>> Chelyabinsk, Russia
>>>> email: rms85 at physics.susu.ac.ru
>>>> web: http://www.susu.ac.ru
>>>>
>>>>
>>>> ------------------------------------------------------------------------
>>>>
>>>>
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>>>
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>
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--
P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671 FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at WWW: http://info.tuwien.ac.at/theochem/
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