Emerging Versatile Two‐Dimensional MoSi2N4 Family.

The discovery of 2D layered MoSi2N4 and WSi2N4 without knowing their 3D parents by chemical vapor deposition in 2020 has stimulated extensive studies of 2D MA2Z4 system due to its structural complexity and diversity as well as versatile and intriguing properties. Here, a comprehensive overview on the state‐of‐the‐art progress of this 2D MA2Z4 family is presented. Starting by describing the unique sandwich structural characteristics of the emerging monolayer MA2Z4, their versatile properties including mechanics, piezoelectricity, thermal transport, electronics, optics/optoelectronics, and magnetism is summarized and anatomized. The property tunability via strain engineering, surface functionalization and layered strategy is also elaborated. Theoretical and experimental attempts or advances in applying 2D MA2Z4 to transistors, photocatalysts, batteries and gas sensors are then reviewed to show its prospective applications over a vast territory. New opportunities are further discussed and prospects are suggested for this emerging 2D family. The overview is anticipated to guide the further understanding and exploration on 2D MA2Z4. [ABSTRACT FROM AUTHOR]