[Wien] [EXTERNAL] Re: Where am I making mistake in LDA+U MAE calculation

[Parker, David S.]

I would add to Peter's comments that generally, for a 2D hexagonal system (such as SmFe5)
The struct file to use is the one given by initso (and symmetso) for a planar orientation of the 
Moments - I usually use (110).  A similar comment applies to a tetragonal system; for rhombohedral
I use (1,-1,0) (note that in these rhombohedral coordinates the c-axis is (111)).  For a cubic case
it seems that the struct file should have only inversion symmetry, as this and the identity are
the only common elements to the (100), (110) and (111) directions. The only input file that should differ 
for the c-axis and planar total energy calculations is case.inso - everything else should be identical, with the exception
Of the WIEN2K-computed Fermi energy in case.in1.

Regarding Sm, one often gets meta-stable states that produce spurious MAE results on the order of hundreds
Of meV per unit cell.  If your energy difference is this large it is nearly certain to be a spurious (untrue) result.
To deal with these one must play around with the density matrix - one way that sometimes
works is to take the density matrix from the lowest energy direction and substitute into the 
metastable configuration.

Good luck - David Parker

On 6/11/19, 10:29 AM, "Wien on behalf of Peter Blaha" <wien-bounces at zeus.theochem.tuwien.ac.at on behalf of pblaha at theochem.tuwien.ac.at> wrote:

    Definitely, MAE calculations should ALWAYS be done with ONE struct file 
    of lowest symmetry (eventually in P1) to avoid any possible biases.
    
    Usually initso will change your struct file and reduce symmetry. Take 
    the reduced symmetry file and put another magnetization direction. 
    Repeat such that at the end no further symmetry change appears in any of 
    your desired directions.
    
    With this struct file do a non-SO calculation with -orb (PS: You should 
    NEVER use   -orb right after init_lapw, but always converge first with 
    GGA, then create new dmatup/dn files (x lapwdm -up/dn); save and then 
    continue with -orb.
    
    Obviously, LDA+U can lead to different (meta-stable) solutions and then 
    a comparison of total energies is not possible.
    
    On 6/9/19 6:13 AM, Tuvshin D wrote:
    > Dear WIEN2k users, while my normal MAE calculations are being well 
    > achieved, LDA+U or inclusion of Orbital Potential methods giving not so 
    > reliable results, makes me wonder if I'm doing correct or not. I'd 
    > really appreciate if anyone with an experience on MAE calculations make 
    > quick skim through my steps and point out where did I went wrong. System 
    > is SmFe and calculating DM and U only on Sm atom. Full list of my given 
    > commands are included.
    > 
    > 1. I make directory, bring struct file and run (init_lapw)
    > 2. Set proper case.indm case.indmc and case.inorb files and run 
    > (runsp_lapw -p -orb -ec 0.000001 -cc 0.000001 -fc 0.001 -i 500 -NI)
    > 3. After reached convergence, (save_lapw -d name) to save results.
    > 4. Make 2 new directory for each magnetization directions and copy above 
    > result to them.
    > 5. Run initso_lapw for setup on each of directions.
    > 6. Now run (runsp_lapw -p -so -orb -ec 0.000001 -cc 0.000001 -fc 0.001 
    > -i 500 -NI)
    > 7. Get MAE from difference between energy of 2 directions (from bottom 
    > of case.scf) as -orb already calculated DM.
    > 
    > Is there any wrong steps, if I were to run SO first then scf, what would 
    > be its step, or should I include -orb after normal scf.
    > 
    > Thanks for your kind attention, best of all.
    > 
    > 
    > 
    > 
    > Mailtrack 
    > <https://mailtrack.io?utm_source=gmail&utm_medium=signature&utm_campaign=signaturevirality5&> 
    > 	Sender notified by
    > Mailtrack 
    > <https://mailtrack.io?utm_source=gmail&utm_medium=signature&utm_campaign=signaturevirality5&> 
    > 06/09/19, 1:10:23 PM 	
    > 
    > 
    > _______________________________________________
    > Wien mailing list
    > Wien at 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
    > 
    
    -- 
    
                                           P.Blaha
    --------------------------------------------------------------------------
    Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
    Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
    Email: blaha at theochem.tuwien.ac.at    WIEN2k: http://www.wien2k.at
    WWW:   http://www.imc.tuwien.ac.at/TC_Blaha
    --------------------------------------------------------------------------
    _______________________________________________
    Wien mailing list
    Wien at 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