Negative Poisson's ratio materials are a class of meta-materials that exhibit unique properties when subjected to external tensile forces. They expand in the direction of the applied force and also undergo anomalous expansion in the direction perpendicular to the force. This characteristic has significant engineering applications, including in damping, cushioning, and bulletproof materials. However, most two-dimensional materials do not display pronounced negative Poisson's ratio properties, and very few materials exhibit this behavior in both directions simultaneously. In this new study, researchers have discovered that single-layer SiS2 and its derivatives (MX2) possess this unique property.
Through first-principles simulations, it was found that single-layer SiS2 exhibits a significant negative Poisson's ratio in the direction perpendicular to the plane, with a value of -1.09, and in-plane, with a value of -0.13. When Si is replaced by Sn, the resulting SnS2 single-layer exhibits an even higher negative Poisson's ratio of -1.79 in the direction perpendicular to the plane. Additionally, these materials demonstrate excellent light absorption properties, and their electronic properties remain stable under deformation.
The research results suggest that two-dimensional MX2 single layers are an ideal platform for exploring negative Poisson's ratio properties. This study may advance further research and applications of two-dimensional materials with negative Poisson's ratio properties. The research paper, titled "High Out-of-Plane Negative Poisson’s Ratio and Strong Light Harvesting in Two-Dimensional SiS2 and its derivatives," was published on September 12, 2023, in the journal "Nanoscale."
The first affiliated institution for this research work is Hefei University of Technology. The first author is Associate Researcher Haidi Wang from the Department of Physics, and the corresponding authors are Dr. Xiao-Feng Liu and Professor Zhong-Jun Li from the Department of Physics. This research received support from the National Natural Science Foundation of China and other funding sources.
Link to the original research paper: https://doi.org/10.1039/D3NR04483A
