Tunable Negative Poisson's Ratio in Van der Waals Superlattice.

Xiaowen Li,Yubo Zhang,Zhenhao Gong,Xiaobin Qiang,Penglai Gong,Lang Chen

doi:10.34133/2021/1904839

Xiaowen Li, Yubo Zhang + Show 4 more

Open Access

https://doi.org/10.34133/2021/1904839

Copy DOI

Abstract

Negative Poisson's ratio (NPR) materials are functional and mechanical metamaterials that shrink (expand) longitudinally after being compressed (stretched) laterally. By using first-principles calculations, we found that Poisson's ratio can be tuned from near zero to negative by different stacking modes in van der Waals (vdW) graphene/hexagonal boron nitride (G/h-BN) superlattice. We attribute the NPR effect to the interaction of pz orbitals between the interfacial layers. Furthermore, a parameter calculated by analyzing the electronic band structure, namely, distance-dependent hopping integral, is used to describe the intensity of this interaction. We believe that this mechanism is not only applicable to G/h-BN superlattice but can also explain and predict the NPR effect in other vdW layered superlattices. Therefore, the NPR phenomenon, which was relatively rare in 3D and 2D materials, can be realized in the vdW superlattices by different stacking orders. The combinations of tunable NPRs with the excellent electrical/optical properties of 2D vdW superlattices will pave a novel avenue to a wide range of multifunctional applications.

Highlights

Negative Poisson’s ratio (NPR) material shrinks laterally when axially compressed or laterally expands when subjected to axial stretching
The NPR effect has been found in some two-dimensional (2D) materials [19], such as black phosphorus [20, 21], δ-phosphorene [22], borophene [23, 24], graphene [25], h-BN [26], 1 T-type transition metal dichalcogenides [27], group-IV monochalcogenides [28], Be5C2 [29], silicon dioxide [30, 31], FeB6 [32], B4N [33], and Ag2S [34]
Based on our theoretical calculations, unlike pure 2D materials, the NPR in the van der Waals (vdW) heterostructure can only be maintained around -0.1, which is due to the expansion amplitude of pz orbital under in-plane strain

Summary

Introduction

Negative Poisson’s ratio (NPR) material shrinks laterally when axially compressed or laterally expands when subjected to axial stretching. When subjected to out-of-plane bending moments, the NPR material will exhibit a dome shape rather than the PPR material tending to saddle shape. These excellent properties indicate that the NPR materials have broad application prospects in the automotive, aerospace, marine, and other industrial fields [3]. There are hundreds of thousands of materials in the inorganic crystal structure database (ICSD); the number of NPR materials reported in the study is a few hundred, which is relatively small. Based on our theoretical calculations, unlike pure 2D materials, the NPR in the vdW heterostructure can only be maintained around -0.1, which is due to the expansion amplitude of pz orbital under in-plane strain

Methods

Results

Conclusion