[Pw_forum] question on constraint magnetic moment calculation

[Nguyen Chuong]

Dear Pang Rui,

starting_magnetization on atomic type i in a spin polarized calculation
(such as nspin=2). Values range of starting_magnetization at -1 (all spin
down for the valence electrons of atom) to 1 (all spin-up).
Following this link:

http://www.quantum-espresso.org/wp-content/uploads/Doc/INPUT_PW.html#idp113952


On Fri, Jul 4, 2014 at 3:36 PM, Gabriele Sclauzero <
gabriele.sclauzero at mat.ethz.ch> wrote:

> Dear Pang Rui,
>
>      It's difficult to judge just from the input. Has the scf converged?
> What are the final values of theta for the two atoms? Can you report the
> relevant part of the output?
>
> GS
>
> On 06/28/2014 11:40 AM, Pang Rui wrote:
> > Dear all
> > Could anyone gave me some suggestion to do the constraint magnetic moment
> > calculation?
> > I followed the constraint magnetic moment calculation of the following
> > handson with PWSCF.
> > http://www.vasp.at/vasp-workshop/slides/handsonIV.pdf
> > VASP uses the same method of PWSCF on constraint MM. However, I found the
> > constraint energy is difficult to go zero. In the handson, they use
> > lambda=50eV, got a constraint energy of 0.22591E-03eV. I used
> lambda=150Ry,
> > but got a constraint energy=0.35Ry. Even PWSCF is different with VASP on
> > some detail, I think it is not reasonable for two codes showing so large
> > difference. So could anyone point the unreasonable part of my input file?
> > Or give me some suggestion? This puzzled me for quite a long time.
> > The following is the input file.
> > &system
> >      ibrav=  0, nat=  2, ntyp= 2,
> >      ecutwfc = 80.0,
> >      occupations='smearing',
> >      degauss=0.001,
> >      smearing='gauss'
> >      starting_magnetization(1)=2.5
> >      starting_magnetization(2)=2.5
> >      angle1(1)=0.0
> >      angle1(2)=45.0
> >      angle2(1)=0.0
> >      angle2(2)=90.0
> >      constrained_magnetization="atomic direction"
> >      noncolin=.ture.
> >      lambda=150.0
> >      nosym=.true.
> > /
> >   &electrons
> >      mixing_beta = 0.1
> >      electron_maxstep=200
> >      startingwfc='file'
> >      startingpot='file'
> >   /
> > ATOMIC_SPECIES
> >   Fe1 56 Fe.pbe-spn-kjpaw_psl.0.2.1.UPF
> >   Fe2 56 Fe.pbe-spn-kjpaw_psl.0.2.1.UPF
> > ATOMIC_POSITIONS angstrom
> > Fe1 3.0 0.0 0.0
> > Fe2 5.0 0.0 0.0
> > K_POINTS automatic
> > 1 1 1 0 0 0
> > CELL_PARAMETERS angstrom
> >      8.0    0.0000000000000000    0.0000000000000000
> >      0.0 8.0    0.0000000000000000
> >      0.0 0.0 8.0
> >
> > PS1: I found the PWSCF used starting_magnetization as
> magnetization/charge
> > for generating initial wave function,but used it as magnetization in
> > constraint MM. So I set 2.5 for them.
> > PS2: The startingwfc is of a smaller lambda calculation.
>
>
> --
> Dr. Gabriele Sclauzero
> ETH Zurich
> Materials Theory
> HIT G 43.2
> Wolfgang-Pauli-Str. 27
> 8093 Zürich, Switzerland
>
> Phone +41 44 633 94 10
> Fax +41 44 633 14 59
> gabriele.sclauzero at mat.ethz.ch
> http://www.theory.mat.ethz.ch/people/postdocs/gsclauze
>
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>



-- 
Nguyen Van Chuong
PhD Student,
Department of Physics,
Don State Technical University.
Rostov on Don, Russia
Group Graphene
Email: chuongnguyen11 at gmail.com or c <cpuphys86 at gmail.com>hnguyen at d
<hnguyen at dstu.edu.ru>stu.edu.ru
Website: http://cpuphys86.webs.com/
Phone mobile: +7 905 45 94 888
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