magnopy.SpinHamiltonian.p421#

property

property SpinHamiltonian.p421#

Parameters of (four spins & two sites (3+1)) term of the Hamiltonian.

\[\boldsymbol{J}_{4,2,1}(\boldsymbol{r}_{\nu,\alpha\beta})\]

of the term

\[\begin{split}C_{4,2,1} \sum_{\substack{\mu, \nu, \alpha, \beta,\\ i, j, u, v}} J^{ijuv}_{4,2,1}(\boldsymbol{r}_{\nu,\alpha\beta}) S_{\mu,\alpha}^i S_{\mu,\alpha}^j S_{\mu,\alpha}^u S_{\mu+\nu,\beta}^v\end{split}\]
Returns:
parametersiterator

List of parameters. The list has a form of

[[alpha, beta, nu, J], ...]

where

alpha is an index of the atom located in the (0,0,0) unit cell.

beta is an index of the atom located in the nu unit cell.

nu defines the unit cell of the second atom (beta). It is a tuple of 3 integers.

J is a (3, 3, 3, 3) numpy.ndarray.

See also

add_421
remove_421