Slow phonon vortices and defect modes in periodic nano-waveguides

TL;DR

This paper reveals a class of slow-moving phonon vortex modes in periodic nano-waveguides, which can be engineered for applications in sensing and nano-manipulation by controlling band-edge properties and defect modes.

Contribution

It introduces the concept of slow phonon vortices associated with split band-edges and demonstrates how waveguide design can support defect modes with minimal frequency splitting.

Findings

Phonon vortices can persist at arbitrarily slow velocities.

Waveguide design enables control over split band-edges.

Defect modes with small frequency splitting can be engineered.

Abstract

We identify a broad class of phonon modes with persistent vortex fluxes at arbitrarily slow propagating velocities in periodic nano-waveguides. Such phonon vortices are associated with the split band-edges in dispersion dependencies, which can be engineered by waveguide design. Modulations introduced in such waveguides can support a pair of defect cavity phonon modes with an arbitrarily small frequency splitting. These features can find applications for sensing and nano-manipulation.