[Pw_forum] Constrained magnetic calculation

Lorenzo Paulatto lorenzo.paulatto at impmc.upmc.fr
Mon Mar 3 13:24:38 CET 2014


On 03/03/2014 12:39 PM, paresh rout wrote:
> Dear all,
>          I am doing  spin polarized  calculations on a multiferroic
> compound . In some cases I am doing constrained magnetic calculations
> to get the Low-spin and High-spin state . For this I am using
>     constrained_magnetization='atomic'
>     starting_magnetization(1) = 5.0
>     starting_magnetization(2) = -3.0
>     starting_magnetization(3) = 0.0
>     starting_magnetization(4) = 0.0
>          lambda =0,5,10,20,25,........etc
>


   +--------------------------------------------------------------------
   Variable:       starting_magnetization(i), i=1,ntyp

   Type:           REAL
   Description:    starting spin polarization on atomic type 'i' in a spin
                   polarized calculation.*Values range between -1 (all
spins**
**                   down for the valence electrons of atom type 'i') to 1**
**                   (all spins up)*. Breaks the symmetry and provides a
starting
                   point for self-consistency. The default value is
zero, BUT a
                   value MUST be specified for AT LEAST one atomic type
in spin
                   polarized calculations, unless you constrain the
magnetization
                   (see "tot_magnetization" and
"constrained_magnetization").
                   Note that if you start from zero initial
magnetization, you
                   will invariably end up in a nonmagnetic (zero
magnetization)
                   state. If you want to start from an antiferromagnetic
state,
                   you may need to define two different atomic species
                   corresponding to sublattices of the same atomic type.
                   starting_magnetization is ignored if you are performing a
                   non-scf calculation, if you are restarting from a
previous
                   run, or restarting from an interrupted run.
                   If you fix the magnetization with "tot_magnetization",
                   you should not specify starting_magnetization.
   +--------------------------------------------------------------------


kind regards

-- 
Dr. Lorenzo Paulatto 
IdR @ IMPMC -- CNRS & Université Paris 6
phone:+33 (0)1 44275 084 / skype: paulatz
www:  http://www-int.impmc.upmc.fr/~paulatto/
mail: 23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 5

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