View source for Constraining the local magnetic moments

Description: Constraining the local magnetic moments on NiO.

To orientate locally each spin, a penalty energy E<sub>p</sub> is added, inversely proportional to the LAMBDA parameter. Thus, the process has to begin with a low LAMBDA, which is increased step by step.

For additional informations, go to the [[I_CONSTRAINED_M|I_CONSTRAINED_M]] page.

''<u>Exercise :</u>'' Verify the E<sub>p</sub>=f(1/LAMBDA) relation by constraining the spin directions. Check the efficiency of the method by constraining only the direction, then the direction and the size of spins.

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*{{TAG|INCAR}}

 NiO GGA+U Constr.
   {{TAGBL|SYSTEM}}        = "NiO"
    
 Electronic minimization
   {{TAGBL|ENCUT}}         = 450
   {{TAGBL|EDIFF}}         = 1E-5
   {{TAGBL|LORBIT}}        = 11
   {{TAGBL|LREAL}}         = .False.
   {{TAGBL|ISYM}}          = -1
   {{TAGBL|NELMIN}}        = 6
   {{TAGBL|LSORBIT}}       = .True.
   {{TAGBL|GGA_COMPAT}}    = .FALSE.
    
 DOS
   {{TAGBL|ISMEAR}}    = -5
    
 Magnetism
   {{TAGBL|ISPIN}}     = 2
   {{TAGBL|I_CONSTRAINED_M}} = 1  # direction
   # {{TAGBL|I_CONSTRAINED_M}} = 2  # size and direction
   {{TAGBL|M_CONSTR}}  = 2 0 0 0 -2 0 6*0
   {{TAGBL|LAMBDA}}    = 1
   {{TAGBL|RWIGS}}     = 1.30 0.70 
     
 Orbital moment
   {{TAGBL|LORBMOM}}  = T
     
 Mixer
   {{TAGBL|AMIX}}      = 0.2
   {{TAGBL|BMIX}}      = 0.00001
   {{TAGBL|AMIX_MAG}}  = 0.8
   {{TAGBL|BMIX_MAG}}  = 0.00001
     
 GGA+U
   {{TAGBL|LDAU}}      = .TRUE.
   {{TAGBL|LDAUTYPE}}  = 2
   {{TAGBL|LDAUL}}     = 2 -1
   {{TAGBL|LDAUU}}     = 5.00 0.00
   {{TAGBL|LDAUJ}}     = 0.00 0.00
   {{TAGBL|LDAUPRINT}} = 2
   {{TAGBL|LMAXMIX}}   = 4 
 
*{{TAG|KPOINTS}}
<pre>
k-points
 0
gamma
 4  4  4 
 0  0  0
</pre>

*{{TAG|POSCAR}}
<pre>
NiO
 4.17
 1.0 0.5 0.5
 0.5 1.0 0.5
 0.5 0.5 1.0
 2 2
Cartesian
 0.0 0.0 0.0
 1.0 1.0 1.0
 0.5 0.5 0.5
 1.5 1.5 1.5
</pre>

== Used INCAR Tags ==
{{TAG|AMIX}}, {{TAG|AMIX_MAG}}, {{TAG|BMIX}}, {{TAG|BMIX_MAG}}, {{TAG|EDIFF}}, {{TAG|ENCUT}}, {{TAG|GGA_COMPAT}}, {{TAG|I_CONSTRAINED_M}}, {{TAG|ISMEAR}},{{TAG|ISPIN}}, {{TAG|ISYM}}, {{TAG|LAMBDA}}, {{TAG|LDAU}}, {{TAG|LDAUJ}}, {{TAG|LDAUL}}, {{TAG|LDAUPRINT}}, {{TAG|LDAUTYPE}}, {{TAG|LDAUU}}, {{TAG|LMAXMIX}}, {{TAG|LORBIT}}, {{TAG|LREAL}}, {{TAG|LSORBIT}}, {{TAG|M_CONSTR}}, {{TAG|NELMIN}}, {{TAG|RWIGS}}, {{TAG|SYSTEM}}

== Download ==
[http://www.vasp.at/vasp-workshop/examples/nio_constr.tgz nio_constr.tgz]
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[[VASP_example_calculations|To the list of examples]] or to the [[The_VASP_Manual|main page]]

[[Category:Examples]]