[Pw_forum] magnetic anisotropy calculation using fully-relativistic PPs
petercybertron at gmail.com
Fri Sep 11 21:10:31 CEST 2015
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' ,
mixing_mode = 'local-TF' ,
mixing_beta = 0.9 ,
diagonalization = 'david' ,
Which parameter on earth keep my calculations non-converged?
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