[Wien] Problem with DOS for Fe-Pd system

Maxim Rakitin rms85 at physics.susu.ac.ru
Wed Apr 28 09:32:30 CEST 2010


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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>>> Wien mailing list
>>> Wien at zeus.theochem.tuwien.ac.at
>>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>
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