Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University, Shanghai 200072, People's Republic of China. Institute of Structural Mechanics, Bauhaus-University Weimar, Marienstraße 15, D-99423 Weimar, Germany.
Nanotechnology. 2013 Nov 1;24(43):435705. doi: 10.1088/0957-4484/24/43/435705. Epub 2013 Oct 2.
We derive, from an empirical interaction potential, an analytic formula for the elastic bending modulus of single-layer MoS2 (SLMoS2). By using this approach, we do not need to define or estimate a thickness value for SLMoS2, which is important due to the substantial controversy in defining this value for two-dimensional or ultrathin nanostructures such as graphene and nanotubes. The obtained elastic bending modulus of 9.61 eV in SLMoS2 is significantly higher than the bending modulus of 1.4 eV in graphene, and is found to be within the range of values that are obtained using thin shell theory with experimentally obtained values for the elastic constants of SLMoS2. This increase in bending modulus as compared to monolayer graphene is attributed, through our analytic expression, to the finite thickness of SLMoS2. Specifically, while each monolayer of S atoms contributes 1.75 eV to the bending modulus, which is similar to the 1.4 eV bending modulus of monolayer graphene, the additional pairwise and angular interactions between out of plane Mo and S atoms contribute 5.84 eV to the bending modulus of SLMoS2.
我们从经验相互作用势能推导出单层 MoS2（SLMoS2）弹性弯曲模量的解析公式。通过这种方法，我们不需要为 SLMoS2 定义或估计一个厚度值，这很重要，因为对于石墨烯和纳米管等二维或超薄纳米结构，定义这个值存在很大的争议。我们得到的 SLMoS2 的弹性弯曲模量为 9.61eV，明显高于石墨烯的 1.4eV，并且发现它在使用薄壳理论和实验获得的 SLMoS2 弹性常数值范围内。与单层石墨烯相比，弯曲模量的增加归因于 SLMoS2 的有限厚度。具体来说，虽然每个 S 原子单层对弯曲模量的贡献为 1.75eV，与单层石墨烯的 1.4eV 弯曲模量相似，但平面外 Mo 和 S 原子之间的额外成对和角度相互作用对 SLMoS2 的弯曲模量贡献为 5.84eV。
