Potential 2D Materials with Phase Transitions: Structure, Synthesis, and Device Applications

Layered materials with phase transitions, such as charge density wave (CDW) and magnetic and dipole ordering, have potential to be exfoliated into monolayers and few‐layers and then become a large and important subfamily of two‐dimensional (2D) materials. Benefitting from enriched physical properties from the collective interactions, long‐range ordering, and related phase transitions, as well as the atomic thickness yet having nondangling bonds on the surface, 2D phase‐transition materials have vast potential for use in new‐concept and functional devices. Here, potential 2D phase‐transition materials with CDWs and magnetic and dipole ordering, including transition metal dichalcogenides, transition metal halides, metal thio/selenophosphates, chromium silicon/germanium tellurides, and more, are introduced. The structures and experimental phase‐transition properties are summarized for the bulk materials and some of the obtained monolayers. In addition, recent experimental progress on the synthesis and measurement of monolayers, such as 1T‐TaS2, CrI3, and Cr2Ge2Te6, is reviewed. 2D materials with phase transitions, such as charge density wave and magnetic and dipole orderings, are an important subfamily of 2D materials. Strong charge–spin–lattice couplings in the materials enable vast potentials for new‐concept and new‐structure devices. Recent experimental progress on the synthesis and device demonstration based 2D phase‐transition materials, such as 1T‐TaS2, CrI3, and Cr2Ge2Te6 monolayers, is reviewed.