treams.expandlattice

treams.expandlattice(lattice=None, kpar=None, basis=None, modetype=None, *, eta=0, k0=None, material=Material(1, 1, 0), poltype=None, where=True)

Expansion matrix in lattices.

Expand the modes from one basis set which are assumed to be periodically repeated on a lattice into another basis set.

Parameters:

  • lattice (Lattice or array-like, optional) – Lattice definition. In some cases this argument can be omitted, when the lattice can be inferred from the basis.

  • kpar (sequence, optional) – The components of the wave vector tangential to the lattice. In some cases this argument can be omitted, when the lattice can be inferred from the basis.

  • basis (BasisSet or tuple) – Basis set, if it is a tuple of two basis sets the output and input modes are taken accordingly, else both sets of modes are the same.

  • k0 (float, optional) – Wave number.

  • eta (float or complex, optional) – Split parameter used when the Ewald summation is applied for the lattice sums. By setting it to 0 the split is set automatically.

  • material (Material or tuple, optional) – Material parameters.

  • modetype (str, optional) – Wave mode, used for PlaneWaveBasisByComp.

  • poltype (str, optional) – Polarization, see also Polarizations.

  • where (array-like, bool, optional) – Only evaluate parts of the expansion matrix, the give array must have a shape that matches the output shape.