`Of course! The local moments in an AF insulator can be anything. I just`

`saw that there is only one type of magnetic atom in the unit cell (Ir)`

`and did not think properly. Sorry for that one.`

--- Dr. Martin Pieper Karl-Franzens University Institute of Physics Universitätsplatz 5 A-8010 Graz Austria Tel.: +43-(0)316-380-8564

Am 07.08.2017 09:18, schrieb Peter Blaha:

The Ir moments are read from case.scf file, but why should it be near an integer, and what is the unit of the reported moments in case.scffile? If the unit is bohr magneton, then for a spin 1/2, should it be~1.7?For a FERROmagnetic insulator, the TOTAL spin moment/cell must be integer. The moments of individual atoms can have any value. For an ANTIferromagnet, the total spin moment/cell must be zero, and of course the atomic moments can again have any value. What you get by :MMT or MMIxxx are spin moments only. The moments are given in Bohr magnetons (mu_B), but are the spin moments, not the effective moments. Thus if you have one unpaired electron the spin moment is one. PS: For your compound, the orbital moments are probably as important as the spin moments and you must add them to get the total moment.The gap can be roughly seen along the k-path I plotted and is checkedbyDOS plot, which shows it's an insulator. Yours sincerely, Hung-Yu On Sun, Aug 6, 2017 at 11:03 AM, pieper <pie...@ifp.tuwien.ac.at <mailto:pie...@ifp.tuwien.ac.at>> wrote: A few thoughts on this: ad 1)Presumably Ir is the magnetic ion, so what you describe seems tobeok with me. I did not check your .struct file, however. ad 2) See chapters 4.5.6 and 7.4 of the UG (Wien2k 17.1) on therorb-program, and the references therein. Personally I found thefile of his talk on LDA+U very usefull that E. Assmann posted ontheWien2k-site. Note the recommendation in the UG for the SIC-mode of orb for of strongly correlated systems: set J=0 and use only U_eff=U-J. The value of U_eff is something you will have to decide, perhaps based on the approach described by Madsen and Novak cited in the UG. Youalso might want to take a look at eece as an alternative (UGchapter4.5.7)>From many comments here in the mailing list and from the UG(againe.g. chapter 5.5.7, 4.5.8) I take it that PBE is what you shoulddoif you want to calculate spacial charge and spin distributions,butto calculate gaps you may have to switch to numerically much more costly hybrid methods. You probably can (mis)use U_eff as a free parameter to adjust the gap in your PBE calculation to your favorite value. However, thephysical meaning of the value would be dubious (imho), and thereisno guarantee that the Ir-moments simultaneously come near yourfavorit 'theoretical moments' (whatever the actual value andoriginof those is). ad 3) Don't bother with the starting values of local moments for atomic configurations, and for an antiferromagnet the interstitial moment obviously should stay close to zero. But the moments you give in your table are very far from integer. Are this Ir-spin moments from case.scf or did you add orbital moemnts calculated by lapwdm? The spin moments should be somewhere near integer for an insulator.So, how did you determine the gap in the table? Did you plot aDOS?Is this really an insulator, or are there in fact bands crossingE_F? You might severly misjudge the (direct?) gap depending onwherein k-space it is and the points in your k-list. Good luck --- Dr. Martin Pieper Karl-Franzens University Institute of Physics Universitätsplatz 5 A-8010 Graz Austria Tel.: +43-(0)316-380-8564 <tel:%2B43-%280%29316-380-8564> Am 04.08.2017 19:22, schrieb Hung Yu Yang: Dear WIEN2k developers and users,I am trying to do a calculation on Na2IrO3, which has a bandgap~340meV and a zigzag antiferromagnetic order in its ground state, and I have some questions as follow: 1. To assign the zigzag antiferromagnetic order, what I did is that Ifirst made a cif file that has two inequivalent Ir atoms, andletWIEN2k decide the symmetry for me. I adopted the generated structural file (attached in this mail), checked the cif file in some visulization software and made sure they were structurally equivalentexcept that there were 2 inequivalent Ir atoms instead of 1.Is thisthe proper way to generate structural files for magneticallyorderedsystems?2. After generating the desired structural file, I put up onIr1atomand down on the other (Ir2), used several differentcombinationsof U and J, and I got the following results:U(eV) J(eV) Ueff=U-J (eV) Moment(Ir1,Ir2)Gap(meV) 2.1 0.6 1.5 0.22532,-0.22439 ~700meV 2.4 0 2.4 0.30105,-0.30109 ~750meV 3 0.6 2.4 0.23225,-0.23235 ~900meV 3 1.5 1.5 0.17203,-0.17210 ~900meV First, in this test, it seems that the gap is affected by U only, notUeff=U-J. Second, the moments of Ir seemed to be closelyrelatedto J. In this situation, what is the proper way to assign U and J? I am notsure how much it means if I just try to tune U and J untiltheymatch the experimental gap and/or theoretical moments.3. I also have a question about the unit of moment given here;Iunderstand that the moments depend on the RMT sizes and I assumed theunit is in bohr magneton, but the first value shown for Iratom is0.76697 and I am not sure in what unit is this value and howitassigns the initial moment for a certain element (say, Ir inmycase).Also, the interstitial moments are nearly 0 among all thecycles.For this calculation, kpoints=450, RKmax=8 and I had to usethe TEMPscheme for it to converge. I appreciate any reply from you. Yours sincerely, Hung-Yu _______________________________________________ Wien mailing list Wien@zeus.theochem.tuwien.ac.at <mailto:Wien@zeus.theochem.tuwien.ac.at> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien <http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien> SEARCH the MAILING-LIST at:http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html<http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html>_______________________________________________ Wien mailing listWien@zeus.theochem.tuwien.ac.at<mailto:Wien@zeus.theochem.tuwien.ac.at>http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien <http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien> SEARCH the MAILING-LIST at:http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html<http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html>_______________________________________________ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wienSEARCH the MAILING-LIST at:http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html

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