Band unfolding with a general transformation matrix: from code implementation to interpretation of photoemission spectra

Unfolding of a supercell band structure into primitive Brillouin zone is important for understanding implications structural distortions, disorder, defects, and solid solutions on materials electronic structure. The necessity unfolding also recognised in the interpretation angle-resolved photoemission spectroscopy (ARPES) measurements. We describe an extension fold2Bloch package by implementing arbitrary transformation matrix used to establish relation between cell supercell. This development allows us overcome limitations supercells constructed exclusively scaling lattice vectors. It becomes possible transform conventional cells as well include rotations. publicly available from GitHub repository FORTRAN code. interfaces with all-electron full-potential WIEN2k pseudopotential VASP density functional theory packages. supplemented additional pre- post-processing utilities that aid generating k points (such they later fall onto desired path after unfolding) plotting unfolded selected illustrative example and, first time, present its properly direct comparison ARPES In addition, critical importance data illustrated discussed perspective.