# Elastic Weyl points and surface arc states in 3D structures

## TL;DR

This paper demonstrates the design of 3D elastic structures inspired by Weyl physics, revealing topologically protected surface states and elastic Fermi arcs through numerical simulations, with potential applications in vibration control and energy harvesting.

## Contribution

It introduces a novel 3D elastic lattice structure exhibiting Weyl points and topological surface states, bridging topological physics and elastic engineering.

## Key findings

- Existence of Weyl points with opposite charges in the elastic structure
- Visualization of directional, robust topological surface states
- Potential for vibration control and energy harvesting applications

## Abstract

The study of Weyl points in electronic systems has inspired many recent researches in classical systems such as photonic and acoustic lattices. Here we show how the Weyl physics can also inspire the design of novel elastic structures. We construct a single-phase 3D structure, an analogue of the AA-stacked honeycomb lattice, and predict the existence of Weyl points with opposite topological charges (${\pm 1}$), elastic Fermi arcs, and the associated gapless topologically protected surface states. We employ full-scale numerical simulations on the elastic 3D structure, and present a clear visualization of topological surface states that are directional and robust. Such designed lattices can pave the way for novel vibration control and energy harvesting on structures that are ubiquitous in many engineering applications.