Topological phonons and Weyl lines in 3 dimensions

TL;DR

This paper explores three-dimensional lattice structures with topologically protected phonon states, revealing Weyl lines and surface modes that vary with surface wavenumber, advancing the understanding of topological phononics.

Contribution

It introduces generalized pyrochlore lattices with topologically protected edge states and Weyl lines, expanding the class of topological phononic materials.

Findings

Presence of Weyl lines in bulk phonon spectra

Zero surface modes that switch edges with surface wavenumber

Generalization of pyrochlore lattices with topological features

Abstract

Topological mechanics and phononics have recently emerged as an exciting field of study. Here we introduce and study generalizations of the three-dimensional pyrochlore lattice that have topologically protected edge states and Weyl lines in their bulk phonon spectra, which lead to zero surface modes that flip from one edge to the opposite as a function of surface wavenumber.