[Pw_forum] magnetic anisotropy calculation using fully-relativistic PPs

[peter]

Hi Fang,

I read the paper and found no explicit comparison between USPP and PAW. 
So do you imply PAW is better?

best,
Yun-Peng

On 09/12/2015 02:42 PM, yuewen.fang wrote:
> Hi, Yun-Peng,
>
> Thanks for your feedback. It depends on the matter which you are 
> interested in.  I think this paper (Phys. Rev. B 86, 085135 (2012)) 
> can help you.
>
> Bests
> Fang
>
> ------------------------------------------------------------------------
>
> Yue-Wen FANG, PhD candidate
>
> East China Normal University <http://english.ecnu.edu.cn/>
>
>
> < peter <mailto:petercybertron at gmail.com>> 2015-09-13 02:16:28 wrote:
>
>     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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