treams.SMatrices.bands_kz

SMatrices.bands_kz(az)

Band structure calculation.

Calculate the band structure for the given S-matrix, assuming it is periodically repeated along the z-axis. The function returns the z-components of the wave vector \(k_z\) and the corresponding eigenvectors \(v\) of

\[\begin{split}\begin{pmatrix} S_{\uparrow \uparrow} & S_{\uparrow \downarrow} \\ -S_{\downarrow \downarrow}^{-1} S_{\downarrow \uparrow} S_{\uparrow \uparrow} & S_{\downarrow \downarrow}^{-1} (\mathbb{1} - S_{\downarrow \uparrow} S_{\uparrow \downarrow}) \end{pmatrix} \boldsymbol v = \mathrm{e}^{\mathrm{i}k_z a_z} \boldsymbol v\,.\end{split}\]

Parameters:

az (float) – Lattice pitch along the z direction

Returns:

tuple