Oh, that's great! Since I am using a supercell which is a 2x2 repetition of the unit cell for Cu2N (which is, itself, built upon a 2x2 repetition of the Cu(100) slab without N atoms), I suppose I won't have to go much further than the k-point sampling I am currently using for the non-spin-polarized relaxation of the supercell. I will, however, perform convergence tests.
Merci beaucoup for the comments! Best, Marcos On Thu, Jul 12, 2018 at 1:57 PM, BARRETEAU Cyrille <[email protected] > wrote: > For the Co slab of the example I would suggest 20x20x1 kpoints for scf (no > SOC) calculation and 40x40x1 kpoints for the nscf (with SOC) calculations. > But you should check convergence. > > For bulk calculations MAE is extremely complicated to extract since in > cubic systems the MAE is of the order of 10^(-5)eV!!! Almost impossible to > achieve a converged result! > > 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: [email protected] > Web: http://iramis.cea.fr/Pisp/cyrille.barreteau/ > ======================== > ------------------------------ > *De :* users [[email protected]] de la part de > Marcos Veríssimo Alves [[email protected]] > *Envoyé :* jeudi 12 juillet 2018 13:32 > > *À :* Quantum Espresso users Forum > *Objet :* Re: [QE-users] Magnetic anisotropy energy in QE 6.3 > > 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 < > [email protected]> 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: [email protected] >> Web: http://iramis.cea.fr/Pisp/cyrille.barreteau/ >> ======================== >> ------------------------------ >> *De :* users [[email protected]] de la part de >> Marcos Veríssimo Alves [[email protected]] >> *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 < >> [email protected]> 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: [email protected] >>> Web: http://iramis.cea.fr/Pisp/cyrille.barreteau/ >>> ======================== >>> ------------------------------ >>> *De :* users [[email protected]] de la part de >>> Paolo Giannozzi [[email protected]] >>> *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 < >>> [email protected]> 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 >>>> [email protected] >>>> 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 >>> >>> _______________________________________________ >>> users mailing list >>> [email protected] >>> https://lists.quantum-espresso.org/mailman/listinfo/users >> >> >> _______________________________________________ >> users mailing list >> [email protected] >> https://lists.quantum-espresso.org/mailman/listinfo/users >> > > > _______________________________________________ > users mailing list > [email protected] > https://lists.quantum-espresso.org/mailman/listinfo/users >
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