National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
Nanoscale. 2017 Jun 22;9(24):8126-8132. doi: 10.1039/c7nr02070h.
The structural phase transition in MoS promises applications in novel nanoelectronic devices. Elastic strain engineering can not only serve as a potential route for phase transition engineering, but also reveal potential ferroelastic behavior of MoS nanostructures. However, the elastic strain required for phase transition in monolayer MoS is far beyond its elastic limit, thus inhibiting the experimental realization. In this study, employing density functional theory calculations, we uncover that by forming heterostructure with buckled 2D materials, such as silicene, germanene and stanene, the critical phase transition strain required in monolayer MoS can be drastically reduced. Particularly when MoS forms sandwiched structures with silicene or stanene, the uniaxial and biaxial critical strain can be reduced to ∼0.06 and ∼0.03, respectively, which is well below the experimental elastic limit. This theoretical study not only proposes an experimental achievable strategy for flexible phase transition design in MoS nanostructure, but also identifies those MoS heterostructures as 2D candidates for potential shape memory devices and pseudoelasticity applications.
MoS 的结构相变有望在新型纳米电子器件中得到应用。弹性应变工程不仅可以作为相变工程的一种潜在途径，还可以揭示 MoS 纳米结构的潜在铁弹性行为。然而，单层 MoS 相变所需的弹性应变远远超出了其弹性极限，从而抑制了实验的实现。在这项研究中，通过使用密度泛函理论计算，我们发现通过与褶皱二维材料（如硅烯、锗烯和锡烯）形成异质结构，可以显著降低单层 MoS 所需的临界相变应变。特别是当 MoS 与硅烯或锡烯形成夹心结构时，单轴和双轴临界应变可分别降低到约 0.06 和 0.03，远低于实验弹性极限。这项理论研究不仅为 MoS 纳米结构中灵活的相变设计提出了一种可实验实现的策略，还确定了这些 MoS 异质结构作为潜在形状记忆器件和伪弹性应用的二维候选材料。
