A research team from the USTB Institute for Advanced Materials and Technology and the USTB Beijing Advanced Innovation Center for Materials Genome Engineering designed a new layered structure material. The research results were published in the journal Science on March 24^th, 2023, titled "Ferroelectricity in layered bismuth oxide down to 1 nanometer". USTB is the first research unit, and Ms. YANG Qianqian, a Ph.D. candidate from the Institute for Advanced Materials and Technology, is the first author of this paper. Professor ZHANG Linxing and Professor TIAN Jianjun are the corresponding authors. Professor XING Xianran and Professor CHEN Jun guided this work.

Cover of the issue

Atomic-scale ferroelectrics are of great interest for high-density electronics, particularly field-effect transistors, low-power logic, and nonvolatile memories. We devised a film with a layered structure of bismuth oxide that can stabilize the ferroelectric state down to 1 nanometer through samarium bondage. This film can be grown on various substrates with a cost-effective chemical solution deposition. We observed a standard ferroelectric hysteresis loop down to a thickness of ~1 nanometer. The thin films with thicknesses that range from 1 to 4.56 nanometers possess a relatively large remanent polarization from 17 to 50 microcoulombs per square centimeter. We verified the structure with first-principles calculations, which also pointed to the material being a lone pair–driven ferroelectric material. The structure design of the ultrathin ferroelectric films has great potential for the manufacturing of atomic-scale electronic devices.

Group photo of the research team

Mr. HU Jingcong, a Ph.D. student at the Beijing Univeristy of Technology, and Mr. FANG Yuewen, a researcher at the Universidad del País Vasco (Spain), are the co-first authors Mr. LU Yue, an associate researcher of USTB, is the co-corresponding author. The cooperation units include Tel Aviv University (Israel), Shanghai Jiaotong University, the University of Science and Technology of China, and the Chinese Academy of Sciences.

Link: https://www.science.org/doi/10.1126/science.abm5134