magnopy.LSWT.delta

method

LSWT.delta(k, relative=False, units='meV')

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 Units of 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