[Wien] Magnetocrystalline anisotropy

Tue Jan 16 15:28:50 CET 2018

I also agree on this comment. However, we did exactly the same 
calculations in WIEN2k_16 and WIEN2k_17 (P1, full kmesh, EECE, RKMAX ...).

Thus I do not expect that the problem comes from this suggestion in this 
specific case.

Le 16/01/2018 à 15:26, Laurence Marks a écrit :
> Dear Xavier,
>
> One other suggestion, with a caveat. In general if the physical model
> is weak/wrong or there are coding errors, the convergence is poor.
> This has to do with what I call "noise" in the calculation (for want
> of a better term). Since the mixing is implicitly a Simplex derivative
> noise matters.
>
> The first caveat is that there can be large change in the orbital
> occupancies with -so/orb. This is a rotation of the density matrix or
> orbital potential, and rotations are poorly handled in Taylor
> expansions (which all mixers are).
>
> The second caveat is that when one reduces symmetry there can be
> additional soft modes which only poorly converge.
>
> On Tue, Jan 16, 2018 at 8:09 AM, Xavier Rocquefelte
> <xavier.rocquefelte at univ-rennes1.fr> wrote:
>> Dear Laurence
>>
>> Here is the point. Our results show that in version 17 a problem occurs
>> related to the time-reversal, which appears only if we do GGA+U or EECE.
>>
>> a) The calculations we showed are already done in P1. Indeed, I wanted
>> to avoid any problems related to symmetry.
>>
>> b) we (me and my PhD student William Lafargue-dit-Hauret) were exactly
>> working along this line ... our preliminary results are not consistent.
>>
>> c) we didn't try this option ... we will try
>>
>> Thank you for your quick reply Laurence
>>
>> Best Regards
>>
>> Xavier
>>
>>
>>
>> Le 16/01/2018 à 15:03, Laurence Marks a écrit :
>>> I may annoy Peter with the comment below, so it goes....
>>>
>>> Personally I have some reservations about the consistency between the
>>> orbital potential and time-reversal operations in -so. Three possible
>>> tests:
>>>
>>> a) Reduce the symmetry to P1 and run. While this is slower, I believe
>>> your test case is small so this should not matter.
>>> b) Hack the runsp_lapw script so that -orb is applied to lapw1, not in lapwso
>>> c) Run without the up/dn component (-noorbud)
>>>
>>> On Tue, Jan 16, 2018 at 7:50 AM, Xavier Rocquefelte
>>> <xavier.rocquefelte at univ-rennes1.fr> wrote:
>>>> Here is a document showing the results graphically.
>>>>
>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__filesender.renater.fr_-3Fs-3Ddownload-26token-3D8ac3a214-2Dedfa-2D4894-2Dfa1f-2D27aba5a5522f&d=DwIGaQ&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=mfZINSS9VKVdzwe4U7cSmx0-ziyAHYu8JU6ZTl7KjeM&s=4O827iUX43sWWhwFi99lMba-6xHX3nxPAXPuikEN73k&e=
>>>>
>>>> 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
>>>>
>>>> _______________________________________________
>>>> Wien mailing list
>>>> Wien at zeus.theochem.tuwien.ac.at
>>>> https://urldefense.proofpoint.com/v2/url?u=http-3A__zeus.theochem.tuwien.ac.at_mailman_listinfo_wien&d=DwIGaQ&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=mfZINSS9VKVdzwe4U7cSmx0-ziyAHYu8JU6ZTl7KjeM&s=opwywLds3-6-KYjkJUfKJV-4G6EJb440GEUuoV4O9Vs&e=
>>>> SEARCH the MAILING-LIST at:
>>>> https://urldefense.proofpoint.com/v2/url?u=http-3A__www.mail-2Darchive.com_wien-40zeus.theochem.tuwien.ac.at_index.html&d=DwIGaQ&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=mfZINSS9VKVdzwe4U7cSmx0-ziyAHYu8JU6ZTl7KjeM&s=jnRVI0-0BEr1i0sOPY4obcMGj22Zt6aPVwTaFzcI7_k&e=
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> Wien mailing list
>>>> Wien at zeus.theochem.tuwien.ac.at
>>>> https://urldefense.proofpoint.com/v2/url?u=http-3A__zeus.theochem.tuwien.ac.at_mailman_listinfo_wien&d=DwIGaQ&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=mfZINSS9VKVdzwe4U7cSmx0-ziyAHYu8JU6ZTl7KjeM&s=opwywLds3-6-KYjkJUfKJV-4G6EJb440GEUuoV4O9Vs&e=
>>>> SEARCH the MAILING-LIST at:
>>>> https://urldefense.proofpoint.com/v2/url?u=http-3A__www.mail-2Darchive.com_wien-40zeus.theochem.tuwien.ac.at_index.html&d=DwIGaQ&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=mfZINSS9VKVdzwe4U7cSmx0-ziyAHYu8JU6ZTl7KjeM&s=jnRVI0-0BEr1i0sOPY4obcMGj22Zt6aPVwTaFzcI7_k&e=
>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> Wien mailing list
>>>> Wien at zeus.theochem.tuwien.ac.at
>>>> https://urldefense.proofpoint.com/v2/url?u=http-3A__zeus.theochem.tuwien.ac.at_mailman_listinfo_wien&d=DwIGaQ&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=mfZINSS9VKVdzwe4U7cSmx0-ziyAHYu8JU6ZTl7KjeM&s=opwywLds3-6-KYjkJUfKJV-4G6EJb440GEUuoV4O9Vs&e=
>>>> SEARCH the MAILING-LIST at:
>>>> https://urldefense.proofpoint.com/v2/url?u=http-3A__www.mail-2Darchive.com_wien-40zeus.theochem.tuwien.ac.at_index.html&d=DwIGaQ&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=mfZINSS9VKVdzwe4U7cSmx0-ziyAHYu8JU6ZTl7KjeM&s=jnRVI0-0BEr1i0sOPY4obcMGj22Zt6aPVwTaFzcI7_k&e=
>>>>
>>>>
>>>
>> _______________________________________________
>> Wien mailing list
>> Wien at zeus.theochem.tuwien.ac.at
>> https://urldefense.proofpoint.com/v2/url?u=http-3A__zeus.theochem.tuwien.ac.at_mailman_listinfo_wien&d=DwIGaQ&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=mfZINSS9VKVdzwe4U7cSmx0-ziyAHYu8JU6ZTl7KjeM&s=opwywLds3-6-KYjkJUfKJV-4G6EJb440GEUuoV4O9Vs&e=
>> SEARCH the MAILING-LIST at:  https://urldefense.proofpoint.com/v2/url?u=http-3A__www.mail-2Darchive.com_wien-40zeus.theochem.tuwien.ac.at_index.html&d=DwIGaQ&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=mfZINSS9VKVdzwe4U7cSmx0-ziyAHYu8JU6ZTl7KjeM&s=jnRVI0-0BEr1i0sOPY4obcMGj22Zt6aPVwTaFzcI7_k&e=
>
>