[Wien] Magnetocrystalline anisotropy
Peter Blaha
pblaha at theochem.tuwien.ac.at
Wed Jan 17 10:07:52 CET 2018
But mixing is switched off in case.inorb !!
On 01/17/2018 09:54 AM, William Lafargue-dit-Hauret wrote:
> Dear Prof. Blaha and Marks,
>
> Thank you for your comments and suggestions.
>
> Looking at the SRC_orb/main.f, orb seems to read potential files to mix
> with old vorb files.
>
> William
>
>
> Le 17/01/2018 à 08:03, Peter Blaha a écrit :
>> Just a few comments:
>>
>> In many posts to this topic I saw the -c switch. This is not
>> necessary and prone to errors. Don't use -c . It will be done
>> automatically.
>>
>> I think, the orb program reads case.dmat* files, and produces
>> case.vorb* files. It is not reading vorb files.
>> And it does read the complex part !!!
>>
>> And third: the vorb* potential should be applied only once.
>>
>> It can be done in x lapw1 -orb -up/dn OR in
>> x lapwso -orb -up
>> but not in both.
>>
>> Application in lapwso also includes cross terms between spin-up and
>> dn, while in lapw1 it excludes them.
>>
>> When reporting differences between wien2k_16 and 17, you have to find
>> out, what causes these differences.
>> a) compare case.vorbup/dn in both cases. Are they the same/similar ?
>> In particular with respect to symmetry (+m and -m terms symmetric ???)
>> b) run lapwso of 17 with vorbs of 16 and vice versa.
>>
>> If nothing helps, send me your struct file + some details (inputs) and
>> I'll check it myself.
>>
>> Peter
>>
>>
>> Am 16.01.2018 um 17:57 schrieb William Lafargue-dit-Hauret:
>>> Dear Profs. Blaha and Marks,
>>>
>>> Thank you for your advices. I have a question regarding your comment
>>> on the EECE case.
>>>
>>> The resulting effective potential of LDA+U and EECE corrections is
>>> decomposed in vorb files, but I don't understand why the
>>> spin-coupling file case.vorbud shouldn't appear in the second case.
>>>
>>> I have a second question regarding the reading of these orbital
>>> potential files. We noticed the orb program read only the real part,
>>> neglecting the imaginary one (Prof. Marks already noticed it in the
>>> source code). Due to our energy scale which is tiny, could we expect
>>> an impact of such approximation ? Considering your last comments, it
>>> seems not due to the execution of the orb program only in lapw1 and
>>> not during the perturbative procedure.
>>>
>>> Thank you by advance.
>>>
>>> All the best,
>>>
>>> William Lafargue-dit-Hauret
>>>
>>>
>>> Le 16/01/2018 à 17:05, Xavier Rocquefelte a écrit :
>>>> I was not clear Peter. I clarify the way we proceed.
>>>>
>>>> We do runsp_lapw -eece -p -ec 0.00001 -NI
>>>>
>>>> Then for larger EMAX and kmesh without SO we do :
>>>>
>>>> x lapw1 -up -c -orb
>>>> x lapw1 -dn -c -orb
>>>>
>>>> And for the different magnetization directions we do:
>>>>
>>>> x lapwso -c -up -orb
>>>> x lapw2 -so -up -c
>>>> x lapw2 -so -dn -c
>>>>
>>>>
>>>>
>>>>
>>>> Le 16/01/2018 à 16:58, Peter Blaha a écrit :
>>>>> Hups: If this is true, you are counting the orbital potential twice !
>>>>>
>>>>> -orb should only be present in the lapwso step.
>>>>> (And in fact, the lapw1 steps need to be done just once for the
>>>>> increased k-mesh; but not when changing the M-direction in case.inso)
>>>>>
>>>>> Please check the presence of case.vorbud. It must not be there for
>>>>> EECE.
>>>>>
>>>>> You could also test Laurence suggestion, running:
>>>>>
>>>>> x lapw1 -up/dn -orb
>>>>> x lapwso -up (no -orb !!!)
>>>>>
>>>>> and see of it makes a difference.
>>>>>
>>>>> On 01/16/2018 04:52 PM, Xavier Rocquefelte wrote:
>>>>>> Dear Peter
>>>>>>
>>>>>> You are totally correct. We are doing SO non-selfconsistent by
>>>>>> using a standard procedure for EECE calculations:
>>>>>>
>>>>>> runsp_lapw -eece -p -ec 0.00001 -NI
>>>>>>
>>>>>> and then we estimate the MAE using this non-SCF procedure :
>>>>>>
>>>>>> Increase EMAX in case.in1c - increase kmesh if needed ....
>>>>>>
>>>>>> x lapw1 -up -c -orb
>>>>>> x lapw1 -dn -c -orb
>>>>>> x lapwso -c -up -orb
>>>>>> x lapw2 -so -up -c
>>>>>> x lapw2 -so -dn -c
>>>>>>
>>>>>> Such a procedure was working nicely in previous WIEN2k versions.
>>>>>> Best Regards
>>>>>> Xavier
>>>>>>
>>>>>>
>>>>>>
>>>>>> Le 16/01/2018 à 16:34, Peter Blaha a écrit :
>>>>>>> Hallo Xavier,
>>>>>>>
>>>>>>> Looks rather strange.
>>>>>>>
>>>>>>> Eventually I would have expected problems both, in 16.1 and 17.1
>>>>>>> (but not 14.2) due to the off-diagonal density matrices. But this
>>>>>>> should concern ONLY LDA+U, not -eece.
>>>>>>>
>>>>>>> Just to be sure:
>>>>>>>
>>>>>>> I expect you do SO non-selfconsistent, so vorbup/dn(du) files are
>>>>>>> always the same ?? (just running lapwso and lapw2 -so)
>>>>>>>
>>>>>>> Did you make sure that for -eece -so, case.vorbud is NOT present
>>>>>>> (from previous LDA+U).
>>>>>>>
>>>>>>> Peter
>>>>>>>
>>>>>>>
>>>>>>> On 01/16/2018 02:50 PM, Xavier Rocquefelte wrote:
>>>>>>>> Here is a document showing the results graphically.
>>>>>>>>
>>>>>>>> https://filesender.renater.fr/?s=download&token=8ac3a214-edfa-4894-fa1f-27aba5a5522f
>>>>>>>>
>>>>>>>>
>>>>>>>> It really looks like the problem we had before (using bad kmesh).
>>>>>>>>
>>>>>>>> We test it on two different compounds and in both cases
>>>>>>>> WIEN2k_16 gives a correct picture and not WIEN2k_17.
>>>>>>>>
>>>>>>>> We are now comparing the two versions of the code.
>>>>>>>>
>>>>>>>> Regards
>>>>>>>>
>>>>>>>> Xavier
>>>>>>>>
>>>>>>>>
>>>>>>>> Le 16/01/2018 à 12:10, Xavier Rocquefelte a écrit :
>>>>>>>>>
>>>>>>>>> Dear All
>>>>>>>>>
>>>>>>>>> Finally the problem is not completely solved.
>>>>>>>>>
>>>>>>>>> More precisely, when we are doing GGA+SO calculations and using
>>>>>>>>> a correct kmesh (no temporal symmetry), we obtain a symmetric
>>>>>>>>> magnetocrystalline anisotropy, namely same MAE along [0 1 0]
>>>>>>>>> and [0 -1 0].
>>>>>>>>>
>>>>>>>>> In contrast, when we are doing GGA+U+SO or EECE+SO with a
>>>>>>>>> correct kmesh we still obtain non-symmetric MAE, namely MAE
>>>>>>>>> along [0 1 0] and [0 -1 0] are different.
>>>>>>>>>
>>>>>>>>> In addition, the so obtained MAE looks similar to the ones
>>>>>>>>> obtained in GGA+SO with a bad kmesh (including temporal symmetry).
>>>>>>>>>
>>>>>>>>> At this moment, we are checking all the recent modifications in
>>>>>>>>> SRC_ORB and SRC_LAPW2 related to the manipulation of
>>>>>>>>> case.vorbup, case.vorbdn and case.vorbud files.
>>>>>>>>>
>>>>>>>>> Surprisingly, the EECE+SO calculations in WIEN2k_16 are
>>>>>>>>> symmetric, while not in WIEN2k_17.
>>>>>>>>>
>>>>>>>>> Next soon ... I hope.
>>>>>>>>>
>>>>>>>>> Xavier
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Le 10/01/2018 à 15:10, Xavier Rocquefelte a écrit :
>>>>>>>>>>
>>>>>>>>>> Dear All
>>>>>>>>>>
>>>>>>>>>> The problem is solved and was related to one stupid human
>>>>>>>>>> mistake.
>>>>>>>>>>
>>>>>>>>>> It was necessary to generate a kmesh without adding inversion
>>>>>>>>>> (time-inversion symmetry).
>>>>>>>>>> Indeed, as mentionned in the userguide when using kgen program:
>>>>>>>>>>
>>>>>>>>>> # *"add inversion" ?* This is asked only when inversion is NOT
>>>>>>>>>> present.
>>>>>>>>>>
>>>>>>>>>> * Say *"YES"* in all cases except when you do *spin-polarized
>>>>>>>>>> (magnetic) calculations WITH spin-orbit coupling * (this
>>>>>>>>>> breaks
>>>>>>>>>> time-inversion symmetry and thus one MUST NOT add inversion
>>>>>>>>>> symmetry (eigenvalues at +k and -k may be different).
>>>>>>>>>>
>>>>>>>>>> If you properly generate the kmesh for the spin-orbit
>>>>>>>>>> calculations by doing : x kgen -fbz, then you obtain a
>>>>>>>>>> symmetric magnetic anisotrop. In conclusion the asymmetry I
>>>>>>>>>> obtained was due to an improper definition of the kmesh
>>>>>>>>>> (adding artificially time-inversion).
>>>>>>>>>>
>>>>>>>>>> I want to thank all the participants who answered to my
>>>>>>>>>> question. It was essential to identify such a mistake which
>>>>>>>>>> has a huge impact on the results.
>>>>>>>>>>
>>>>>>>>>> Best wishes
>>>>>>>>>>
>>>>>>>>>> Xavier
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Le 10/01/2018 à 10:47, Xavier Rocquefelte a écrit :
>>>>>>>>>>> Dear Lyudmila
>>>>>>>>>>>
>>>>>>>>>>> The fact we have a small angle with axes is expected (also
>>>>>>>>>>> observed experimentally). It is related to the monoclinic
>>>>>>>>>>> symmetry of the system which permits it. However, you gave me
>>>>>>>>>>> an idea that I will test now and comment soon ;)
>>>>>>>>>>>
>>>>>>>>>>> Cheers
>>>>>>>>>>>
>>>>>>>>>>> Xavier
>>>>>>>>>>>
>>>>>>>>>>> Le 10/01/2018 à 10:40, Lyudmila a écrit :
>>>>>>>>>>>> 10.01.2018 13:36, Lyudmila wrote:
>>>>>>>>>>>>> I see in the FM calculation also a slightly non-symmetric
>>>>>>>>>>>>> curve, isn't it?
>>>>>>>>>>>>
>>>>>>>>>>>> I meant the small angle with axes.
>>>>>>>>>>>>
>>>>>>>>>>>>> Best wishes
>>>>>>>>>>>>> Lyudmila Dobysheva
>>>>>>>>>>>> _______________________________________________
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>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
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>>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> _______________________________________________
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>>>>>>>>
>>>>>>>>
>>>>>>>>
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>>>>>>>>
>>>>>>>
>>>>>>
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>>>>>
>>>>
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>>>
>>> --
>>> William LAFARGUE-DIT-HAURET
>>> PhD Student
>>> --------------------------------------------------
>>> Institut des Sciences Chimiques de Rennes UMR 6226
>>> Equipe Chimie Théorique Inorganique
>>> Université de Rennes 1 - Campus de Beaulieu
>>> 35042 Rennes, France
>>> Building 10B, Desk 211
>>> Phone: +33 (0)2.23.23.57.91
>>> Email:william.lafargue-dit-hauret at univ-rennes1.fr
>>>
>>>
>>>
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>>
>
--
P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
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