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I'm fairly new to DFT. I would like to plot the DOS and band structure of Cobalt Oxide (CoO). But since CoO is anti ferro magnetic, how would I approach the problem? would I create an input file wherein I should assign starting magentization to spins as follows:

enter image description here

by using names like Co1 and Co2 in the Atomic species name card. Or would the act of putting nspin = 2, along with a starting magnetisation for all cobalt atoms suffice? Maybe someone who is experience could shed some light on how to properly model an anti-ferro magentic system.

Thank you.

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    $\begingroup$ Do you want to model the antiferromagnetic interactions themselves? Or just to enforce antiferromagnetic ordering on the simulation? $\endgroup$ – taciteloquence Nov 4 '20 at 17:18
  • $\begingroup$ +1. Excellent first question and welcome to Stack Exchange! Thank you for contributing your question here, and we hope to see much more of you! Also nice diagram for the spins in a magnet, you may be interested to see that I used the same one in this question: mattermodeling.stackexchange.com/q/136/5 (which I closed voluntarily because the question was too hard for anyone to answer, but it can be re-opened if you do think you have an answer to it). $\endgroup$ – Nike Dattani Nov 9 '20 at 17:16
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enter image description here

  • Antiferromagnetic configuration setting: Cr1 ($\uparrow$) / Cr2 ($\downarrow$) / Cr3=Cr1 ($\uparrow$) / Cr4=Cr2 ($\downarrow$)

  • All I atoms are non-magnetic.

  • QE scf input card:

     &CONTROL
        calculation='scf'
        prefix='CrI3'
        outdir='./tmp/'
        pseudo_dir='./pseudo/'
        etot_conv_thr=1.0d-05
     /
     &SYSTEM
        ibrav=0
        nat=16
        ntyp=3
        ecutwfc=60
        ecutrho=720
        occupations='smearing'
        smearing='mp'
        degauss=0.02
        nspin=2
        starting_magnetization(1)= 3  !note that ntype=3
        starting_magnetization(2)=-3
        starting_magnetization(3)= 0
      /
      &ELECTRONS
        conv_thr=1.0d-8
        mixing_beta=0.7
        electron_maxstep=200
      /
      ATOMIC_SPECIES
        Cr1  51.996 cr_pbe_v1.5.uspp.F.UPF
        Cr2  51.996 cr_pbe_v1.5.uspp.F.UPF
        I    126.9045 I.pbe-n-kjpaw_psl.0.2.UPF
      ATOMIC_POSITIONS crystal
        Cr1  0.0000000000  0.0000000000   0.3304567040
        Cr2  0.0000000000  0.3333333430   0.3297766150
        Cr1  0.5000000000  0.5000000000   0.3304567040
        Cr2  0.5000000000  0.8333333730   0.3297766150
        I    0.1495049890  0.1672649980   0.4083212910
        I    0.6495050190  0.6672649980   0.4083212910
        I    0.1743501420  0.4911199810   0.4083212910
        I    0.6743501420  0.9911199810   0.4083212910
        I    0.6761449580  0.3416150210   0.4083212910
        I    0.1761449580  0.8416150210   0.4083212910
        I    0.8504950400  0.1660683450   0.2519120570
        I    0.3504950400  0.6660683160   0.2519120570
        I    0.3256500360  0.3422133330   0.2519120570
        I    0.8256500360  0.8422133330   0.2519120570
        I    0.8238549830  0.4917183820   0.2519120570
        I    0.3238549830  0.9917184110   0.2519120570
      CELL_PARAMETERS angstrom
        6.8670001030       0.0000000000       0.0000000000
        0.0000000000      11.8939924240       0.0000000000
        0.0000000000       0.0000000000      20.0000000000
      K_POINTS automatic
        4 2 2 0 0 0
    
  • Total magnetization in each electronic step:

enter image description here

  • Once you know how to do the self-consistent calculation, all left calculations are easily performed.
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    $\begingroup$ Fantastic, super detailed answer! $\endgroup$ – taciteloquence Nov 10 '20 at 17:53

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