Zheng Hong, Zhao Zhenhan, Chen Jiasheng, Qin Hanwen, Li Jun, Zhao Xiang
State Key Laboratory of Electrical Insulation and Power Equipment, Center of Nanomaterials for Renewable Energy, School of Electrical Engineering, Xi'an Jiaotong University Xi'an 710049 China
Institute for Chemical Physics, School of Chemistry, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi'an Jiaotong University Xi'an 710049 China
Nanoscale Adv. 2025 Mar 31;7(11):3308-3321. doi: 10.1039/d4na00966e. eCollection 2025 May 27.
Designing new auxetic materials is important for flexible electronics. The micromechanism of auxeticity in two-dimensional (2D) materials has attracted significant attention but the main factors of auxeticity are case-dependent and their connection with the geometrical/electronic features of 2D materials still requires systematic exploration. In this work, two new phases of 2D group-VA materials, namely, X10-2_2 and X12-14 (X = P, As, Sb, and Bi), were predicted. All these structures were proven to be stable from the aspects of their thermodynamic and kinetic stabilities. Investigations of their electronic properties revealed that these structures were all semiconductors with high anisotropic mobility. Mechanical analyses showed that all the X12-14 phases exhibited auxeticity, whereas the Poisson's ratios of the X10-2_2 series presented a strong dependence on the group-VA elements. The P10-2_2 structure exhibited auxeticity under both tensile and compression strain. However, As10-2_2 exhibited a peculiar half-auxeticity and Sb10-2_2 and Bi10-2_2 were non-auxetic. Evaluations of the interatomic interaction forces revealed that it is the unique folded structures and the changes of the atomic interactions that induce the different mechanical properties of the X10-2_2 structures. This work uncovers the special relationship between the auxeticity of 2D group-VA materials and the inherent natures of the group-VA elements from the viewpoint of the interatomic interaction force, which will assist future research on auxetic materials.
设计新型负泊松比材料对于柔性电子学至关重要。二维（2D）材料中负泊松比的微观机制已引起广泛关注，但负泊松比的主要影响因素因情况而异，其与二维材料几何/电子特性的关联仍需系统探索。在这项工作中，预测了二维VA族材料的两个新相，即X10 - 2_2和X12 - 14（X = P、As、Sb和Bi）。从热力学和动力学稳定性方面证明，所有这些结构都是稳定的。对其电子性质的研究表明，这些结构均为具有高各向异性迁移率的半导体。力学分析表明，所有X12 - 14相均表现出负泊松比，而X10 - 2_2系列的泊松比强烈依赖于VA族元素。P10 - 2_2结构在拉伸和压缩应变下均表现出负泊松比。然而，As10 - 2_2表现出特殊的半负泊松比，Sb10 - 2_2和Bi10 - 2_2则不具有负泊松比。对原子间相互作用力的评估表明，正是独特的折叠结构和原子相互作用的变化导致了X10 - 2_2结构不同的力学性能。这项工作从原子间相互作用力的角度揭示了二维VA族材料的负泊松比与VA族元素固有性质之间的特殊关系，这将有助于未来对负泊松比材料的研究。
