General Theory for Bilayer Stacking Ferroelectricity

Two-dimensional (2D) ferroelectrics, which are rare in nature, enable high-density nonvolatile memory with low energy consumption. Here, we propose a theory of bilayer stacking ferroelectricity (BSF), in which two stacked layers of the same 2D material, with different rotation and translation, exhibit ferroelectricity. By performing systematic group theory analysis, we find all the possible BSF in all 80 layer groups (LGs) and discover the rules about the creation and annihilation of symmetries in the bilayer. Our general theory can not only explain all the previous findings (including sliding ferroelectricity), but also provide a new perspective. Interestingly, the direction of the electric polarization of…

• NN
  National Natural Science Foundation of China

  Awards: 12174060, 12274082, 11991061, 11825403, 12188101
• MO
  Ministry of Science and Technology of the People's Republic of China

  Award: 2022YFA1402901
• BA
  Basic and Applied Basic Research Foundation of Guangdong Province

  Award: 2021B0301030005