Bao Hongwei, Huang Yuhong, Yang Zhi, Miao Yaping, Sun Yunjin, Bai Yu, Xu Kewei, Ma Fei
State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, Shaanxi, China.
Phys Chem Chem Phys. 2017 Sep 27;19(37):25360-25368. doi: 10.1039/c7cp04799a.
Molecular dynamics (MD) simulations are conducted to study the deformation behavior and strain distribution in two-dimensional (2D) nano-rings of graphene, single-layer black phosphorus (SLBP) and single-layer MoS (SLMoS) under circular torsion. Interestingly, fan-blade shaped wrinkling is generated, in which the maximum torsion angle (Δθ) and the potential energy change per atom (ΔPe) increase with increasing inner radius but decrease with increasing temperature. As the inner radius is increased, the wave number of wrinkling increases but the wave amplitude decreases. The geometrical characteristics of wrinkling are closely related to the intrinsic elastic modulus (E) and Poisson's ratio (ν). Specifically, the graphene nano-rings possess the largest Δθ and ΔPe but the smallest wave amplitude, while the SLBP nano-rings exhibit the smallest Δθ and ΔPe but the largest wave amplitude. Furthermore, the strongly anisotropic E and ν values of SLBP result in orientation-dependent geometrical characteristics of wrinkles, and fan-blade shaped wrinkling with a strain vortex is induced, which might substantially enhance the pseudomagnetic fields and optical funnel effect for the separation of photon-induced electron-hole pairs, and thus be exploited to improve the photoelectric properties of 2D materials.
进行分子动力学（MD）模拟以研究石墨烯、单层黑磷（SLBP）和单层二硫化钼（SLMoS）的二维（2D）纳米环在圆形扭转下的变形行为和应变分布。有趣的是，会产生扇形褶皱，其中最大扭转角（Δθ）和每个原子的势能变化（ΔPe）随内半径的增加而增加，但随温度的升高而降低。随着内半径的增加，褶皱的波数增加但波幅减小。褶皱的几何特征与本征弹性模量（E）和泊松比（ν）密切相关。具体而言，石墨烯纳米环具有最大的Δθ和ΔPe，但波幅最小，而SLBP纳米环表现出最小的Δθ和ΔPe，但波幅最大。此外，SLBP的强各向异性E和ν值导致褶皱的几何特征与取向有关，并诱导出带有应变涡旋的扇形褶皱，这可能会显著增强伪磁场和用于分离光子诱导的电子 - 空穴对的光学漏斗效应，从而可用于改善二维材料的光电性能。
