[Pw_forum] A question about the spin density wave

[Chengyang Li]

Dear all

     When I try to add a spin density wave in an antiferromagnetism structure, I met a problem to set up the magnetism. Usually the projection of the spins should change gradually. In the input file ,it should be changed from a simple AFM structure to a non-linear structure. In my calculation, there are four kinds of atoms with different spin directions, however, when I try to run it I found the output shows they're divided into two groups with opposite spin directions, does anyone have any idea about how to change the input or figure out my possible fault? Another question is how to fix the direction for all the atoms with different directions, it seems like I can only use fix_magnetization to set up an external field and all the spins will have the same direction in the field.  Thank you.


This is my input file.
  &SYSTEM
                       ibrav = 5,
                   celldm(1) = 9.18316017664,
	           celldm(4) = -0.33333333333,
                         nat = 8,
                        ntyp = 4,
                     noncolin = .true.
    starting_magnetization(1) = 0.5
    angle1(1) = 90.0,
    angle2(1) = 0.0,
starting_magnetization(2) = -0.5
    angle1(2) = 90.0,
    angle2(2) = 120,
starting_magnetization(3) = 0.5
    angle1(3) = 90.0,
    angle2(3) = 240,
starting_magnetization(4) = -0.5
    angle1(4) = 90.0,
    angle2(4) = 0,
nonsym=.Ture.,

       
                     ecutwfc = 26.6,
                     ecutrho = 300,
occupations='smearing', smearing='gaussian', degauss=0.01,

 /
 &ELECTRONS
 conv_thr = 1.0d-10,
 mixing_beta = 0.05 ,
electron_maxstep=200
 /
ATOMIC_SPECIES
Cr1    51.99610  Cr.pbe-sp-van.UPF
Cr2    51.99610  Cr.pbe-sp-van.UPF
Cr3    51.99610  Cr.pbe-sp-van.UPF
Cr4    51.99610  Cr.pbe-sp-van.UPF
 
  
ATOMIC_POSITIONS crystal 
Cr1      0.000000000   0.000000000   0.000000000
Cr2      0.500000000   0.000000000   0.000000000
Cr2      0.000000000   0.000000000   0.500000000
Cr2      0.000000000   0.500000000   0.000000000
Cr4      0.500000000   0.500000000   0.500000000
Cr3      0.500000000   0.500000000   0.000000000
Cr3      0.500000000   0.000000000   0.500000000
Cr3      0.000000000   0.500000000   0.500000000
            
K_POINTS automatic 
2 2 2 1 1 1



Chengyang