二维材料因其具有大量的奇异物理特性受到科学界广泛关注。其中，二维过渡金属硫族化合物因其相结构的多样性而具有丰富的电学特性，利用不同相结构之间的相互转换成为了精确调控其电学性能的手段之一。最近，研究发现利用电荷注入能快速诱导二维二碲化钼发生可逆的结构相变，从而实现金属与半导体相之间的快速可逆切换。但是该可逆相变过程中晶格的微观结构动态演化机制尚未探明，且相变机制缺乏在原子层面的解释。本项目拟在透射电镜腔体内对带有微电极的二碲化钼异质结样品施加电压并实时进行原子级高分辨连续成像以观察整个电致相变的原子级动态过程。得到的高分辨原位数据与器件电学性质的测量联动分析，以期建立电致相变过程中微观结构与宏观性能之间的关联。同时结合第一性原理计算对数据进行解释，建立准确的物理模型，以期用实验与理论相结合的手段来理解整个电致可逆相变过程在原子尺度下的发生机制，为以后相变器件制作与性能提高提供指导性建议。

Two-dimensional materials attract intense attentions in the research community owing to their novel physical properties. Moreover, two-dimensional transition-metal dichalcogenides (TMDs) exhibit numerous crystal phases, each of which corresponds to distinct electronic properties. Thus, utilizing the transition of different phases becomes one of the powerful means to precisely engineer the electronic properties of the materials. Recently, it was found that the injection of charges into the MoTe2 crystal could lead to a reversible structural phase transition, realizing a reversible and rapid switching between semiconducting and metallic phase. However, the dynamical microscopic structure evolution of the lattice during such reversible electric-driven phase transition is still elusive, and the mechanism of the transition lack an atomic level understanding. This project aims to resolve the real-time dynamical evolution of the lattice during the reversible electric-driven phase transition at atomic level, by exerting a bias on a MoTe2 heterostructure with micro electrode in an in-situ holder inside a transmission electron microscope (TEM). The high resolution in-situ data will be analyzed in parallel with the electrical measurements of the micro device, to establish the correlation between the microscopic structural evolution and the macroscopic performance change during the electric-driven phase transition. Combing with the first-principle calculations, we try to find the accurate physical model, hoping to understand the mechanism of the reversible electric-driven phase transition in the atomic level. This project will serve as a guidance for the future design and performance engineering of phase-change devices.