DPhon (Decompose Phonon)
To better understand the phonon-property relation, it is a common practice to decompose the phonon-associated property into the contributions of basic phonon/vibration modes (e.g. longitudinal/transverse acoustic/optical mode), and identify the mode(s) that dominate(s) the property. The existing methods rely on labelling the phonon into one of the basic modes (BMs), however, the vibration characteristics of many phonons are different from the definitions of BMs, indicating these methods may give wrong decomposition results. Here we present a new method based on treating the phonon as a mixture of the BMs. By aligning the wave vectors and then projecting the phonon eigenvector onto the eigenvectors of the BMs, we can obtain the weights of the BMs on the given phonon, which can be used to quantify the contribution of each BM to the property. Our method is generally applicable to different kinds of phonon-related properties and to all crystal materials.
Fig. Distributions of the six basic phonon/vibration modes of 2D antimony: out-of-plane acoustic (ZA) (a), TA (b), LA (c), transverse optical (TO) (d), longitudinal optical (LO) (e), and out-of-plane optical (ZO) (f) modes, overlaid with the phonon dispersion (red). The weights of the basic modes on the phonon are shown by the blackness and the size of the dots. Insets show the vibration patterns of the six basic modes, with top view on the left and side view on the right.
This method is published at: https://iopscience.iop.org/article/10.1088/2515-7639/ab2b7c
Email me (yuanyue.liu.microman@gmail.com) if you are interested in having a copy of the code