[Pw_forum] magnetic anisotropy calculation using fully-relativistic PPs

[peter]

Thank you for your suggestions!
I tried using a small mixing beta (0.1~0.2), and tried using reasonable 
cutoff energies (ecutwfc=50, ecutrho=500), now the convergence is much 
better than before (converged down to 10^-6 Ry).
Another question is, I can find ultra-soft and PAW pseudopotentials, 
which one is better for spin-orbit calculations? I am using PBE XC 
functional.

best,
Yun-Peng

On 09/11/2015 08:08 PM, yuewen.fang wrote:
> Dear Yun-Peng,
>
> Plz try to decrease mixing and perform some convergence tests for your 
> cutoff energy to remove the oscillation of the energy! In addition, 
> this oscillation could also be caused by the unreasonable smearing 
> methods for metals.
>
> Bests
> Fang
>
> ------------------------------------------------------------------------
> Sent from YoMail <http://www.yomail.com/?utm_source=signature>
>
> < Peter Cybertron <mailto:petercybertron at gmail.com>> 2015-09-12 
> 03:10:31 wrote:
>
>     Hi,
>
>
>     I am working in University of Florida as a postdoc.
>     I am exploring the spin-orbital calculations using pwscf, and I
>     encounter a very slow convergence like this:
>     > grep estimated scf.out
>     estimated scf accuracy < 0.00000004 Ry
>     ... (100 similar lines)
>     estimated scf accuracy < 0.00000003 Ry
>     > grep "total energy" scf.out
>     ...
>     total energy = -3667.91077719 Ry
>     total energy = -3667.91078176 Ry
>     total energy = -3667.91077642 Ry
>     total energy = -3667.91078300 Ry
>
>
>     Although the convergence of total energy seems OK (down to 0.00001
>     Ry ~
>     0.0001 eV = 0.1 meV), I still feel uncomfortable since I never
>     encounter
>     such a problem without spin-orbit interactions.
>
>
>     I downloaded the ultrasoft and PAW pseudopotentials from PSLib and
>     I am
>     using the PBE flavor of XC functional. The system I am studying is
>     a two
>     dimensional magnetic insulator.
>
>
>     The parameters I am using are:
>     constrained_magnetization = 'total direction'
>     fixed_magnetization(3) = 0.0
>     lambda = 0.2
>     ecutwfc = 30.0 ,
>     ecutrho = 300.0 ,
>     occupations = 'smearing' ,
>     degauss = 0.005,
>     smearing = 'mv' ,
>     nosym=.true.
>     mixing_mode = 'local-TF' ,
>     mixing_beta = 0.9 ,
>     diagonalization = 'david' ,
>
>
>     Which parameter on earth keep my calculations non-converged?
>
>
>     Best,
>     Yun-Peng
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>
>
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