# Band Gap Formation and Tunability in Stretchable Serpentine Interconnects

## TL;DR

This paper demonstrates that serpentine interconnects in flexible electronics can generate and tune phononic band gaps through geometric design and pre-stretch deformation, enabling stretchable and tunable phononic crystals using metallic materials.

## Contribution

It introduces the concept of phononic band gap formation in stretchable serpentine interconnects and shows how to tune these gaps via mechanical deformation, offering a new approach for flexible phononic devices.

## Key findings

- Serpentine interconnects generate phononic band gaps.
- Pre-stretch deformation tunes the band structures.
- Metallic interconnects can replace soft rubber in phononic applications.

## Abstract

Serpentine interconnects are highly stretchable and frequently used in flexible electronic systems. In this work, we show that the undulating geometry of the serpentine interconnects will generate phononic band gaps to manipulate elastic wave propagation. The interesting effect of `bands-sticking-together' is observed. We further illustrate that the band structures of the serpentine interconnects can be tuned by applying pre-stretch deformation. The discovery offers a way to design stretchable and tunable phononic crystals by using metallic interconnects instead of the conventional design with soft rubbers and unfavorable damping.