Recently, a collaboration between Xi'an Jiaotong University, University of Science and Technology of China, Hunan Normal University, Nanjing University, and other institutions has made significant progress in experimental research on two-dimensional layered antiferroelectric materials. For the first time in this system, they achieved intrinsic six-state polarization and proposed the mechanism of intrinsic six-state and four-state realization through vertical ferroelectric/antiferroelectric domain stacking coupling. This achievement was recently published online in Nature Communications.
In this study, the research team successfully synthesized high-quality two-dimensional CuInP2S6 single crystals using chemical vapor transport. By employing piezoresponse force microscopy combined with first-principles calculations, they first demonstrated the six-state intrinsic polarization in CuInP2S6 films. This surpasses the current status quo of achieving the highest number of intrinsic polarizations among numerous ferroelectric materials, including traditional oxide ferroelectrics and van der Waals ferroelectrics. They successfully broke through the limitation of achieving only four-state polarization in three-dimensional and two-dimensional ferroelectric systems. Moreover, during the polarization reversal process of CuInP2S6, they discovered unconventional phenomena different from traditional ferroelectric materials. Specifically, they observed reversible transitions between different polarization states (six, four, and two), challenging the conventional understanding of fixed polarization states in ferroelectric materials.
Related paper information: https://www.nature.com/articles/s41467-024-46891-8
