[Pw_forum] Fwd: pwscf: energy convergence of noncollinear with spin-orbit calculations, withdraw question

[German Samolyuk]

Hello Gabriele,

Thank you for your response and advices.

I used version 4.2.1

the actual (final) input contains instructions:

for magnetization along z-direction

starting_magnetization(1) = 0.1,
starting_magnetization(2) = 0.4,
          noncolin = .true. ,
         angle1(1) = 0,
         angle1(2) = 0,
         angle2(1) = 0,
         angle2(2) = 0,
          lspinorb = .true. ,
   constrained_magnetization = 'atomic direction' ,
            lambda = 0.3,
            nosym = .true.,

and magnetization perpendicular to z-direction

starting_magnetization(1) = 0.1,
starting_magnetization(2) = 0.4,
          noncolin = .true. ,
         angle1(1) = 90,
         angle1(2) = 90,
         angle2(1) = 0,
         angle2(2) = 0,
          lspinorb = .true. ,
   constrained_magnetization = 'atomic direction' ,
            lambda = 0.3,
            nosym = .true.,

the resulting energies  looks reasonable and convergence is really fast.

Thank you for advice with degauss value. I'll check dependence from it.

Best,

German


On Wed, Jun 8, 2011 at 3:55 AM, Gabriele Sclauzero <sclauzer at sissa.it> wrote:
> Hello German,
> Il giorno 01/giu/2011, alle ore 23.02, German Samolyuk ha scritto:
>
> I withdraw my question. It works with nosym=true.
> German
>
>
> ---------- Forwarded message ----------
> From: German Samolyuk <samolyuk at gmail.com>
> Date: Wed, May 18, 2011 at 10:25 AM
> Subject: pwscf: energy convergence of noncollinear with spin-orbit
> calculations
> To: PWSCF Forum <pw_forum at pwscf.org>
>
>
> Dear qe users,
>
> I'm trying to calculate total energy of artificial FCC PtFe compound
> with magnetic moment (MM) along z- and x-directionsi (MAE).
>
> In order to supress oscillation of moment direction I used for MM||z
> calculation
> input instructions
>
>  constrained_magnetization = 'total direction' ,
>   fixed_magnetization(1) = 0.0,
>   fixed_magnetization(2) = 0.0,
>   fixed_magnetization(3) = 1.0,
>
>
> If it is v.>4.2, then a
> Are you sure that this is what you want?
> From the Doc/INPUT_PW:
>                    'total direction':
>                              the angle theta of the total magnetization
>                              with the z axis (theta =
> fixed_magnetization(3))
>                              is constrained:
>
>                              LAMBDA * ( arccos(magnetization(3)/mag_tot) -
> theta )**2
>
>                              where mag_tot is the modulus of the total
> magnetization.
> Then fixed_magnetization(3) = 1.0 does not correspond to the magnetization
> along the z axis (but you should reach the corresponding constrained
> solution anyway, even if different from what you actually want).
> Can you please specify which version of the code you've been using?
> Could you try to compare v.4.1.1 with v.4.3.1 (using the correct value for
> theta=fixed_magnetization(3))
> The constraining potential implemented is different: in the most recent
> version it should work also for theta=90° (magnetization along x), while in
> the previous you could get into troubles, since it was defined as:
>                              LAMBDA * ( magnetization(1) -
> magnetization(3)*tan(theta) )**2
>
> Also convergency should be better in the 4.3.1, though I'm not sure of that.
> You should try to start with local magnetizations on Pt and Fe close to the
> desired target direction. It would be nice if you perform this test.
> Also, reporting only the total energy oscillations is not that useful. You
> should at least report the magnitude and angles of the total magnetization
> while the calculation is going.
> Further advice: from your input, perhaps degauss=0.02 is not enough to get
> accurate magnetizations. I would use at least 0.01, better 0.005.
>
> HTH
>
> GS
>
> However I can not reach total energy convergence and it looks like I
> still have direction oscillation of MM.
>
> What can be done to resolve this problem?
>
> Thank you in advance.
>
> The complete input file for MM||z is and energy accuracy output file
> are attached.
>
> German Samolyuk,
> ORNL, USA
> <ptfe.pw.in><accu.out>_______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
>
>
> § Gabriele Sclauzero, EPFL SB ITP CSEA
>    PH H2 462, Station 3, CH-1015 Lausanne
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
>
>