[QE-users] Magnetic anisotropy energy in QE 6.3

[Marcos Veríssimo Alves]

Thanks for the tip, Cyrille. Should it be increased in the SCF calculation
or in the NSCF one? I would suppose the latter, but of course it's good to
hear the opinion of an expert before wasting human and computer time.

Indeed, there's this paper by Daalderop et al. for bulk Fe, Ni and Co (if
I'm not mistaken) where they highlight this - 100^3 k-points! I suppose
that this would be equivalent to having a 100 x 100 x 100 Monkhorst-Pack
grid?

>From your experience, maybe you could comment on the number of k-points
needed for my particular calculations. The system am working on is a Fe
adatom on a Cu2N surface over Cu(100). I am using a quite large vacuum
layer, of about 18 Ang, along the z direction of a tetragonal cell - would
a dense mesh of k-points then need to be considered only for the kx and ky
directions of the BZ?

Best,

Marcos



On Thu, Jul 12, 2018 at 12:22 PM, BARRETEAU Cyrille <
cyrille.barreteau at cea.fr> wrote:

> Of course to get reliable magnetic anisotropy you should drastically
> increase the number of Kpoints with respect to the example..
>
> Cyrille
>
> ========================
> *Cyrille Barreteau*
> CEA Saclay, IRAMIS, SPEC Bat. 771
> 91191 Gif sur Yvette Cedex, FRANCE
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> +33 1 69 08 38 56 /+33  6 47 53 66 52  (mobile)
> email:     cyrille.barreteau at cea.fr
> Web:     http://iramis.cea.fr/Pisp/cyrille.barreteau/
> ========================
> ------------------------------
> *De :* users [users-bounces at lists.quantum-espresso.org] de la part de
> Marcos Veríssimo Alves [marcos.verissimo.alves at gmail.com]
> *Envoyé :* jeudi 12 juillet 2018 12:10
>
> *À :* Quantum Espresso users Forum
> *Objet :* Re: [QE-users] Magnetic anisotropy energy in QE 6.3
>
> Hello Cyrille and Paolo,
>
> Thanks for the quick response. I was interested really about the inner
> workings, which should be described in the paper that Cyrille mentioned. I
> will take a look at it. The actual execution of the calculation should be
> quite straightforward, from what I saw yesterday in the examples folder.
>
> Once again, thanks to both of you for the response. If I run into any
> problems I'll ask, but hopefully all will be fine.
>
> Best,
>
> Marcos
>
> Em qui, 12 de jul de 2018 10:37, BARRETEAU Cyrille <
> cyrille.barreteau at cea.fr> escreveu:
>
>> Hi Marcos
>>
>> The implementation of the Force Theorem has been described in the
>> following paper:
>> https://journals.aps.org/prb/abstract/10.1103/PhysRevB.90.205409
>>
>> The procedure is the following:
>> first perform a scf calculation with scalar relativistic pseudo
>> then perform  nscf calculation with fully relativistic pseudo (option
>> lforcet=.true., nosym=.true') starting from previous scf charge
>> (startingpot='file') with various spin orientations (theta=0,90 for example)
>> Finally perform a projwfc calculation with  lforcet=.true. and the value
>> of the Fermi level from the nscf calculation (same ef_0 for all
>> calculations).
>>
>> Then you get a file with the energy decomposed over the various atoms and
>> orbitals of the system..
>> The anisotropy is obtained by difference between the different spin
>> orientations.
>>
>> hope it helps..
>>
>> Cyrille
>>
>>
>> ========================
>> *Cyrille Barreteau*
>> CEA Saclay, IRAMIS, SPEC Bat. 771
>> 91191 Gif sur Yvette Cedex, FRANCE
>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> +33 1 69 08 38 56 /+33  6 47 53 66 52  (mobile)
>> email:     cyrille.barreteau at cea.fr
>> Web:     http://iramis.cea.fr/Pisp/cyrille.barreteau/
>> ========================
>> ------------------------------
>> *De :* users [users-bounces at lists.quantum-espresso.org] de la part de
>> Paolo Giannozzi [p.giannozzi at gmail.com]
>> *Envoyé :* jeudi 12 juillet 2018 10:04
>> *À :* Quantum Espresso users Forum
>> *Objet :* Re: [QE-users] Magnetic anisotropy energy in QE 6.3
>>
>> here? PP/examples/ForceTheorem_example/
>>
>> P.
>>
>> On Thu, Jul 12, 2018 at 10:01 AM, Marcos Veríssimo Alves <
>> marcos.verissimo.alves at gmail.com> wrote:
>>
>>> Hi all,
>>>
>>> Browsing QE 6.3's documentation, I saw that MAE can be calculated as a
>>> post-processing step to a pw.x scf calculation. What is the exact procedure
>>> followed? I.e., in the post-processing calculation is the spin density
>>> rotated, and then SOC is included? Is there any reference that details the
>>> procedure used when the MFT is applied in Espresso?
>>>
>>> Best regards,
>>>
>>> Marcos
>>>
>>> _______________________________________________
>>> users mailing list
>>> users at lists.quantum-espresso.org
>>> https://lists.quantum-espresso.org/mailman/listinfo/users
>>>
>>
>>
>>
>> --
>> Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
>> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
>> Phone +39-0432-558216, fax +39-0432-558222
>>
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>
>
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