[Wien] LDA+U, spin up and down

Tran, Fabien fabien.tran at tuwien.ac.at
Wed Mar 4 16:35:05 CET 2020


What are the magnetic moments on the atoms (grep for :MMI in case.scf)? Do atoms 5 and 14 have moments with opposite sign?
What is the value of the band gap of spin up (grep for :GAP in case.scf)?

________________________________________
From: Wien <wien-bounces at zeus.theochem.tuwien.ac.at> on behalf of Ali Baghizhadeh <ali.baghizhadeh at ua.pt>
Sent: Wednesday, March 4, 2020 4:30 PM
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] LDA+U, spin up and down

Dear Fabian
Thank you Fabian. I did not use AFM option, instead I used spin polarized option. For this, I did assig the spin up and down in instgen_lapw and following steps as you mentioned. Before conducting force minimization, the Fe1 and Fe2 are crystallographically equivalent. But after force minimization, there is slight change in some coordinates of both Fe, no longer are equivalent. I did not consider it as negative point, but apparently it is affecting my calculation.
Thank you again.
Ali

-----Original Message-----
From: Wien [mailto:wien-bounces at zeus.theochem.tuwien.ac.at] On Behalf Of Tran, Fabien
Sent: Wednesday, 4 March 2020 16:06
To: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at>
Subject: Re: [Wien] LDA+U, spin up and down

Hi,
>From your previous emails, I understood that you want to do a AFM calculations on LuFeO3.
If the gaps of both spins are not the same, then it means that the resulting magnetic phase is not AFM, but something else (ferromagnetic or ferrimagnetic). There may be two reasons:
1) You started the calculation with an electron density that is not AFM.
2) The Fe atoms (5 and 14) are inequivalent also crystallographically.

To produce a starting AFM electron density execute:
instgen_lapw (and select u,d or n appropriately) x lstart x dstart x dstart -up x dstart -dn

FT

From: Wien <wien-bounces at zeus.theochem.tuwien.ac.at> on behalf of Ali Baghizhadeh <ali.baghizhadeh at ua.pt>
Sent: Wednesday, March 4, 2020 3:50 PM
To: A Mailing list for WIEN2k users
Subject: [Wien] LDA+U, spin up and down


Dear WIEN2k users
I am running spin polarized calculation on LuFeO3 structure, with Fe ions having spin up and down in unit cell. I did volume optimization/force minimization, and then I used LDA+U to open the bandgap. It does work fine for spin up when  I plot the density of states, but for spin down, it is conductive. I cannot explain this behavior, and I do not know how to look for the root/s of the problem. Please any comment will be highly appreciated.

Case.inorb file: (Fe1 is atom 5 and Fe2 is atom 14)
1  2  0                     nmod, natorb, ipr PRATT  1.0                    BROYD/PRATT, mixing
  5 1 2                          iatom nlorb, lorb
  14 1 2                          iatom nlorb, lorb
  1                              nsic 0..AMF, 1..SIC, 2..HFM
   0.367 0.073        U J (Ry)   Note: you can also use U_eff = U-J and J=0
   0.367 0.073        U J

Sincerely
Ali



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