magnopy.LSWT.delta#

method

LSWT.delta(k, relative=False, units='meV')[source]#

Computes constant delta term of the diagonalized Hamiltonian.

\[\sum_{\boldsymbol{k}}\Delta(\boldsymbol{k})\]

Parameters:

k(3,) array-like: Reciprocal vector.
relativebool, default False: If relative=True, then k is interpreted as given relative to the reciprocal unit cell. Otherwise it is interpreted as given in absolute coordinates.
unitsstr, default "meV": Added in version 0.3.0.

Units of energy. See Magnon energies for the full list of supported units.

Returns:

deltafloat: Constant energy term that results from diagonalization. Note, that data type is complex. If the ground state is correct, then the complex part should be zero.

See also

LSWT.diagonalize
LSWT.omega

Examples

>>> import magnopy
>>> spinham = magnopy.examples.cubic_ferro_nn()
>>> lswt = magnopy.LSWT(spinham=spinham, spin_directions=[[0, 0, 1]])
>>> lswt.delta(k=[0, 0, 0.5], relative=True)
0j