The consistent behavior of negative Poissons ratio with interlayer interactions

TL;DR

This study systematically investigates how interlayer interactions affect the negative Poisson's ratio in layered nanostructures, revealing that the NPR remains consistent across different multilayer configurations due to orbital coupling responses.

Contribution

It provides a first-principles analysis showing that interlayer interactions do not alter the NPR in layered nanostructures, offering insights for device design.

Findings

NPR is consistent across single and multilayer structures.

Interlayer interactions do not significantly change the NPR.

Orbital coupling response to strain is the key mechanism.

Abstract

Negative Poissons ratio (NPR) is of great interest due to the novel applications in lots of fields. Films are the most commonly used form in practical applications, which involves multiple layers. However, the effect of interlayer interactions on the NPR is still unclear. In this study, based on first principles calculations, we systematically investigate the effect of interlayer interactions on the NPR by comparably studying single-layer graphene, few-layer graphene, h-BN, and graphene-BN heterostructure. It is found that they almost have the same geometry-strain response. Consequently, the NPR in bilayer graphene, triple-layer graphene, and graphene-BN heterostructure are consistent with that in single-layer graphene and h-BN. The fundamental mechanism lies in that the response to strain of the orbital coupling are consistent under the effect of interlayer interactions. The deep understanding of the NPR with the effect of interlayer interactions as achieved in this study is beneficial for the future design and development of micro-/nanoscale electromechanical devices with novel functions based on nanostructures.