Cell

Cell and atoms are the two data structures that are implemented in a number of codes (if not in each one of them). Magnopy does not re-implement them, but rather use the same data structure as in another python package called wulfric.

Here we briefly describe how the unit cell is stored, if you want to read the original description of wulfric we refer you to key concepts of wulfric.

cell is a two-dimensional \(3\times3\) matrix (array-like), that defines three lattice vectors. The rows of the cell are vectors, while the columns are cartesian coordinates. Here is an example of a simple orthorhombic cell

>>> cell = [
...     [3.553350, 0.000000, 0.000000],
...     [0.000000, 4.744935, 0.000000],
...     [0.000000, 0.000000, 8.760497],
... ]

with the three lattice vectors being

>>> a1 = cell[0]
>>> a2 = cell[1]
>>> a3 = cell[2]

In magnopy cell is used in the definition of Spin Hamiltonian and is one of three objects that are required for the creation of the SpinHamiltonian class. It is stored as an its attribute SpinHamiltonian.cell.