magnopy.SpinHamiltonian.remove_422

method

SpinHamiltonian.remove_422(alpha: int, beta: int, nu: tuple) → None

Removes a (four spins & two sites (2+2)) parameter from the Hamiltonian.

Doubles of the bonds are managed automatically (independently of the convention of the Hamiltonian).

Parameters:

alphaint

Index of an atom from the (0, 0, 0) unit cell.

0 <= alpha < len(spinham.atoms.names).

betaint

Index of an atom from the nu unit cell.

0 <= beta < len(spinham.atoms.names).

nutuple of 3 int

Three relative coordinates with respect to the three lattice vectors, that specify the unit cell for the second atom.

\[\nu = (x_{\boldsymbol{a}_1}, x_{\boldsymbol{a}_2}, x_{\boldsymbol{a}_3})\]

See also

p422

add_422

Notes

If spinham.convention.multiple_counting is True, then this function removes all versions of the bond from the Hamiltonian.

If spinham.convention.multiple_counting is False, then this function removes the primary version of the given bond.

For the definition of the primary version see Multiple counting.

For instance, if (1, 0, (0, 0, 0)) is given, then this function attempts to remove either both (1, 0, (0, 0, 0)) and (0, 1, (0, 0, 0)) if spinham.convention.multiple_counting == True or the primary version (0, 1, (0, 0, 0)) if spinham.convention.multiple_counting == False.