Symmetry-breaking-induced ferroelectric HfSnX3 monolayers and their tunable Janus structures: promising candidates for photocatalysts and nanoelectronics.

Autor: Zhang, Yu, Shen, Yanqing, Liu, Jiajia, Lv, Lingling, Zhou, Min, Yang, Xin, Meng, Xianghui, Zhang, Bing, Zhou, Zhongxiang
Zdroj: Physical Chemistry Chemical Physics (PCCP); 9/14/2023, Vol. 25 Issue 34, p22889-22899, 11p
Abstrakt: Designing novel two-dimensional (2D) ferroelectric materials by symmetry breaking and studying their mechanisms play important roles in the discovery of new ferroelectric photocatalysts and nanoelectronics. In this study, we have systematically investigated a series of novel ferroelectric 2D HfSnX3 (X = S, Se and Te) monolayers through first-principles calculations. We found that each HfSnX3 monolayer contains a stable ferroelectric phase (FP) and a paraelectric phase (PP). The large polarization (up to 1.64 μC cm−2) in the FP can significantly bend the oxidation reduction potential of water, making HfSnX3 monolayers become excellent ferroelectric photocatalysts. Specifically, by designing a Janus structure to break the symmetry of the PP, we have excitingly obtained a stable Hf2GeSnSe6 (referred to as HGSS) monolayer with triple polarized states. HGSS not only possesses great visible light absorption properties (about 3 × 105 cm−1) as photocatalysts but also successfully solves the dead layer problem previously reported in practical applications. In addition, by constructing a heterostructure with graphene, HGSS has great application in the design of controllable ultrathin p–n junctions. Overall, our study not only predicts a series of potential ferroelectric photocatalytic materials, but also provides valuable insights for designing tunable polarized materials and nanoelectronics. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index