# Band Unfolding Made Simple

## TL;DR

This paper introduces a straightforward method for band unfolding in supercell calculations, utilizing the local density of states in reciprocal space, applicable to both periodic and non-periodic systems, and demonstrates its implementation in the SIESTA package with applications to Si and graphene defects.

## Contribution

It presents a simple, intuitive approach to band unfolding based on qLDOS, valid for systems with or without translational symmetry, and provides an implementation in SIESTA.

## Key findings

- Effective band unfolding for defective systems demonstrated
- Method applicable to both periodic and non-periodic structures
- Implementation successfully applied to Si and graphene defects

## Abstract

We present a simple view on band unfolding of the energy bands obtained from supercell calculations. It relies on the relationship between the local density of states in reciprocal space (qLDOS) and the fully unfolded band structure. This provides an intuitive and valid approach not only for periodic, but also for systems with no translational symmetry. By refolding into the primitive Brillouin zone of the pristine crystal we recover the conventional unfolded bands. We implement our algorithm in the SIESTA package and apply it to defects on Si and graphene.