changes the selected matrix inside the sw object
SETMATRIX(obj, 'Option1', Value1, ...)
Input:
obj sw class object.
Options:
One of the below options has to be given:
label Label of the matrix that is already assigned to either as
anisotropy, g-tensor or coupling.
mat_idx Index of the matrix, stored in obj.matrix. Alternative to
the 'label' option.
coupling_idx Value of the obj.coupling.idx, that defines the coupling,
for which the symmetry allowed matrix elements will be set.
aniso_idx Value of the obj.matom.idx, that selects a magnetic atom,
for which the symmetry allowed matrix elements will be
set for single ion anisotropy.
g_idx Value of the obj.matom.idx, that selects a magnetic atoms,
for which the symmetry allowed matrix elements will be
set for the g-tensor.
Optional inputs:
pref Defines prefactors as a vector for the symmetry allowed
components, dimensions are [1 nSymMat]. Alternatively, if only
a few of the symmetry allowed matrices have non-zero
prefactors, use:
{[6 0.1 5 0.25]}
This means, the 6th symmetry allowed matrix have prefactor 0.1,
the 5th symmetry allowed matrix have prefactor 0.25. Since
Heisenberg isotropic couplings are always allowed, a cell with
a single element will create a Heisenberg coupling, example:
{0.1}
This is identical to obj.matrix.mat = eye(3)*0.1
For DM interactions (antisymmetric coupling matrices), use
three element vector in the cell:
{[D1 D2 D3]}
In this case, these will be the prefactors of the 3
antisymmetric symmetry allowed matrices. In case no crystal
symmetry is defined, these will define directly the components
of the DM interaction in the xyz coordinate system. Be
carefull with the sign of the DM interaction, it depends on the
order of the two interacting atoms! Default value is {1}.
For anisotropy matrices antisymmetric matrices are not allowed.
Output:
The selected obj.matrix.mat will contain the new value.
Example:
...
setmatrix(crystal,'label','J1','pref',{[6 0.235]})
This example will set 'J1' coupling to the 6th symmetry allowed matrix,
with prefactor 0.235.
setmatrix(crystal,'label','J2','pref',{1.25})
This will set 'J2' to antiferromagnetic Heisenberg exchange, with value
of 1.25 meV.
See also SW, SW.GENCOUPLING, SW.GETMATRIX.