Elemental Ferroelectricity and Antiferroelectricity in Group‐V Monolayer

• Published in: Advanced functional materials Vol. 28; no. 17
• Main Authors: Xiao, Chengcheng, Wang, Fang, Yang, Shengyuan A., Lu, Yunhao, Feng, Yuanping, Zhang, Shengbai
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 25.04.2018
• Subjects: 2D materials; Antiferroelectricity; Antimony; Atomic structure; Curie temperature; Electric polarization; Ferroelectric materials; Ferroelectricity; group‐V elements; Materials science; Monolayers; Phosphorene; s‐p hybridization; Two dimensional models
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201707383

Ferroelectricity is usually found in compound materials composed by different elements. Here, based on first‐principles calculations, spontaneous electric polarization and ferroelectricity in 2D elemental group‐V (As, Sb, and Bi) monolayer with the puckered lattice structure similar to phosphorene is revealed. These are the first example of elemental ferroelectric materials. The polarization is due to the spontaneous lattice distortion with atomic layer buckling and has quite sizable values, comparable or even larger than that recently found in 2D monolayer compound SnTe. Interestingly, for Bi monolayer, apart from the ferroelectric phase, it is found that it can also host an antiferroelectric phase. The Curie temperatures of these elemental materials can be higher than room temperature, making them promising for realizing ultrathin ferroelectric devices of broad interest. A general model is constructed to understand and search for 2D ferroelectric and antiferroelectric materials in future studies. Robust ferroelectricity is predicted in 2D elemental group‐V (As, Sb, and Bi) monolayers with the puckered lattice structure similar to phosphorene. Interestingly, for Bi monolayer, a metastable antiferroelectric phase is also found. The revealed phase‐change mechanism for such elemental monolayer takes to deeply understand the effect of s‐p hybridization on stability and distortion of 2D system.