Van der Waals layered transition metal dichalcogenides can exist in many different atomic and electronic phases. Such diverse polymorphisms not only provide a route for investigating novel topological states, such as quantum spin Hall insulators, superconductors and Weyl semimetals, but may also have applications in fields ranging from electronic and optical/quantum devices to electrochemical catalysis. And the methods for triggering robust phase transitions between polymorphs are evolving and diversifying—several growth processes, high-pressure/strain methods, and optical, electronic and chemical treatments have been developed. Here, we discuss recent progress on phase transitions and the related physics in layered materials, and demonstrate unique features compared with conventional solid-state materials.

Van der Waals层状过渡金属二硫化氢可以存在许多不同的原子相和电子相中。这种多样的多态性不仅提供了一种研究新颖的拓扑状态的途径，例如量子自旋霍尔绝缘体，超导体和Weyl半金属，而且还可以应用于从电子和光学/量子装置到电化学催化的领域。触发多晶型物之间稳固相变的方法正在发展和多样化，已开发了几种生长过程，高压/应变方法以及光学，电子和化学处理方法。在这里，我们讨论了层状材料在相变和相关物理方面的最新进展，并展示了与传统固态材料相比的独特功能。