magnopy.LSWT.delta#

method

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

Constant energy 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"

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

Added in version 0.3.0.

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