Phonon Unfolding: A program for unfolding phonon dispersions of materials

We present Phonon Unfolding, a Fortran90 program for unfolding phonon dispersions. It unfolds phonon dispersions by using a generalized projection algorithm, which can be used to any kind of atomic systems in principle. Thus our present program provides a very useful tool for the phonon dispersion and vibration mode analysis of surface reconstructions, atomic point defects, alloys and glasses. Program summary Program title: Phonon Unfolding Catalogue identifier: AFBI_v1_0 Program summary URL: http://cpc.cs.qub.ac.ukisummaries/AFBI_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU GPL v3 No. of lines in distributed program, including test data, etc.: 211922 No. of bytes in distributed program, including test data, etc.: 3138246 istribution format: tar.gz Programming language: Fortran 90. Computer: Any computer architecture. Operating system: Linux, Windows, Mac. RAM: System dependent, about 10 MB Classification: 7.1, 7.4, 7.8. External routines: LAPACK, BIAS Nature of problem: The Brillouin zone of a supercell is smaller than that of a primary cell. It makes the supercell phonons more crowded. The crowded phonon dispersions are outright difficult, if not impossible, to be compared with experimental results directly. Besides, the intra-supercell translation symmetries are hidden in the supercell phonon dispersion calculations. In order to compare with experiments and catch the hidden symmetries, we have to unfold the supercell phonon dispersions into the corresponding primary-cell Brillouin zone. Solution method: The phonon polarization vectors are projected to a group of plane waves. The unfolding weight is calculated from these plane wave components. Unusual features: Applicable to general systems without considering which kind of translational symmetry breaking. Simple and user-friendly input system. Great efficiency and high unfolding speed. Running time: System dependent, from a few seconds to one hour. (C) 2016 Published by Elsevier B.V.