Band Unfolding Made Simple

We present a simple point of view on band unfolding of the energy bands obtained from supercell calculations that relies on the relationship existing between the local density of states in reciprocal space (qLDOS) and the fully unfolded band structure of a system. This new concept provides an intuitive and valid approach not only for periodic, but also for non-translationally symmetric systems, as well as a way to recover the conventional band structure by doing a refolding back into the primitive Brillouin zone of the pristine crystal. We implemented this algorithm in the Siesta package and tested some of its potential applications on silicon-based systems, such as defective crystals, surfaces and amorphous structures.