[Wien] fixed-spin-moment and normal spin-polarized calculations

[Peter Blaha]

Hard to say without further details (scf file).
I'd expect the problem could be in the BZ integration (fermi energy,..)

Check the scf file for :NOE   and ':CHA  :' and :NEC01
For NOE=232/224 you should get CHA=116/112 respectively. If you don't, most
likely also the total charge (NEC01) is wrong.

Change k-mesh and/or Fermi method.

> Dear Wien2k Users
> 
> For Mn substitutional doped AlN supercell system, when I tried to compare the
> total energy from the fixed-spin-moment (FSM) scheme with the one from normal
> spin-polarized calculations, I observed quite weird behavior:
> 
> For the normal spin-polarization calculations, the calculation runs well and
> the produced result is as expected---which gives a 4 mu_B/cell, and the total
> energy is -11357.236702 Ry.
> 
> However, if I use the FSM method with the fixed moment = 4 mu_B/cell, the
> calculation looks (only looks!) good, that is, the energy and the charge
> density converged very well, and without any suspicious signals. (in *in2cup,
> the number of spin-up electron is 232, and in *in2cdn, the spin-dn electron
> number is 224 --- which are as expected). But the converged total energy is
> -11356.396458 Ry!  Moreover, the converged total magnetic moment is 5.196
> mu_B, not the expected 4 mu_B!
> 
> Note in these two calculations, I used same structure, same parameters. The
> other difference is that for normal s-p using command "runsp_lapw -cc 0.00001
> -i 40"
> and for the FSM using
> "runfsm_lapw -m 4 -cc  0.00001 -i 40"
> 
> Also I have tried the several bcc-Fe using FSM with different fixed moments
> --- FSM works fine, I got the expected magnetic moments.
> 
> Now I got really puzzled --- it seems that the current FSM is not capable for
> Mn-doped AlN case? --- FSM should be rather straightforward .
> 
> I attached the supercell *.struct file for your inspection.
> 
> Many thanks in advance and best wishes to you all,
> Carl CUI
> 
> School of Physics,
> The University of Sydney, Australia 


                                      P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
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