assigns a predefined matrix as exchange coupling on selected bonds
ADDCOUPLING(obj, matrixLabel, couplingIdx, {bondIdx})
Input:
obj sw class object.
matrixLabel Label of the matrix, or the index.
couplingIdx Selects the interacting atom pairs through the coupling.idx
number. The coupling.idx numbers are in increasing order
according to the distances between magnetic atoms, for
example all shortest interatom distances have idx=1, second
shortest idx=2 and so on. couplingIdx can be vector to
assign the matrix to multiple inequivalent magnetic atom
distances.
bondIdx Selects the indices of bonds within coupling.idx to
differentiate between equal length bonds. If bondIdx
defined, couplingIdx has to be scalar. Optional. If the
crystal symmetry is not P1, bondIdx is not allowed, since
each equivalent coupling matrix will be calculated using
the symmetry operators of the space group. Optional.
Output:
The function adds extra entries in the 'coupling.matrix' field of the obj
sw object.
Example:
...
cryst.addmatrix('label','J1','value',0.123)
cryst.gencoupling
cryst.addcoupling('J1',1)
This will add the 'J1' diagonal matrix to all second shortes bonds
between magnetic atoms.
See also SW, SW.GENCOUPLING, SW.ADDMATRIX.