How can I unfold the band structure of a supercell from SIESTA output?
Band unfolding is done as a post-processing of the SIESTA calculation using the same information as already used to compute Fatbands. Periodicity corresponding to a smaller cell is assumed. It may be approximate because structural distortions or chemical disordered.
A beta version of this post-processing tool is available in SIESTA version 4.1-b4,
see https://blueprints.launchpad.net/siesta/+spec/unfolding1