"Unlocking Bilayer Stacking Ferroelectricity: A General Theory"

Researchers at Fudan University and the Shanghai Qi Zhi Institute have proposed a theory of bilayer stacking ferroelectricity (BSF), which could inform the synthesis of 2D ferroelectrics and offer a generalizable guideline of how two stacked layers of the same 2D material can be engineered to exhibit ferroelectricity. The researchers systematically analyzed a series of 2D material groups using group theory, an abstract algebra theory for studying sets of specific objects, to pinpoint the rules underpinning the creation and annihilation of symmetries in bilayer structures, while also identifying possible combinations that would produce BSF. The general theory of bilayer stacking ferroelectricity introduced by the researchers could soon guide new studies aimed at creating bilayer ferroelectrics, facilitating the development of new highly performing devices based on these promising 2D material systems.