A few thoughts on this: ad 1)

`Presumably Ir is the magnetic ion, so what you describe seems to be ok`

`with me. I did not check your .struct file, however.`

## Advertising

ad 2)

`See chapters 4.5.6 and 7.4 of the UG (Wien2k 17.1) on ther orb-program,`

`and the references therein. Personally I found the .pdf file of his talk`

`on LDA+U very usefull that E. Assmann posted on the Wien2k-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. You also might`

`want to take a look at eece as an alternative (UG chapter 4.5.7)`

`From many comments here in the mailing list and from the UG (again e.g.`

`chapter 5.5.7, 4.5.8) I take it that PBE is what you should do if you`

`want to calculate spacial charge and spin distributions, but to`

`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, the physical`

`meaning of the value would be dubious (imho), and there is no guarantee`

`that the Ir-moments simultaneously come near your favorit 'theoretical`

`moments' (whatever the actual value and origin of 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 a DOS? Is`

`this really an insulator, or are there in fact bands crossing E_F? You`

`might severly misjudge the (direct?) gap depending on where in 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 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 band gap ~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 I first made a cif file that has two inequivalent Ir atoms, and let WIEN2k 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 equivalent except that there were 2 inequivalent Ir atoms instead of 1. Is this the proper way to generate structural files for magnetically ordered systems? 2. After generating the desired structural file, I put up on Ir1 atom and down on the other (Ir2), used several different combinations of 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, not Ueff=U-J. Second, the moments of Ir seemed to be closely related to J. In this situation, what is the proper way to assign U and J? I am not sure how much it means if I just try to tune U and J until they match the experimental gap and/or theoretical moments. 3. I also have a question about the unit of moment given here; I understand that the moments depend on the RMT sizes and I assumed the unit is in bohr magneton, but the first value shown for Ir atom is 0.76697 and I am not sure in what unit is this value and how it assigns the initial moment for a certain element (say, Ir in my case). Also, the interstitial moments are nearly 0 among all the cycles. For this calculation, kpoints=450, RKmax=8 and I had to use the TEMP scheme for it to converge. I appreciate any reply from you. Yours sincerely, Hung-Yu _______________________________________________ Wien mailing list Wien@zeus.theochem.tuwien.ac.at 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

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