美国麻省理工学院Pablo Jarillo-Herrero团队报道了双层氮化硼中的堆积工程铁电性。相关研究成果发表在2021年5月27日出版的国际学术期刊《科学》。

具有稳健极化强度的原子层厚度的2D铁电体为功能异质结构提供了构建基块。由于层状极性晶体的要求，实验实现仍然具有挑战性。

该文中，研究人员展示了一个从非铁电母体化合物通过采用范德华组装工程二维铁电体的合理设计方法。平行叠层的双层氮化硼表现出面外的电极化，该极化取决于叠层顺序而反转。通过相邻层叠石墨烯片的电阻来探测极化转换。由于形成了交错极化的莫尔铁电体，将氮化硼板扭转一个小角度即可改变转换的动力学。

铁电性在保持石墨烯高迁移率的同时仍能持续到室温，为超薄非易失性存储器的潜在应用铺平了道路。

附：英文原文

Title: Stacking-engineered ferroelectricity in bilayer boron nitride

Author: Kenji Yasuda, Xirui Wang, Kenji Watanabe, Takashi Taniguchi, Pablo Jarillo-Herrero

Issue&Volume: 2021/05/27

Abstract: 2D ferroelectrics with robust polarization down to atomic thicknesses provide building blocks for functional heterostructures. Experimental realization remains challenging because of the requirement of a layered polar crystal. Here, we demonstrate a rational design approach to engineering 2D ferroelectrics from a non-ferroelectric parent compound via employing van der Waals assembly. Parallel-stacked bilayer boron nitride exhibits out-of-plane electric polarization that reverses depending on the stacking order. The polarization switching is probed via the resistance of an adjacently stacked graphene sheet. Twisting the boron nitride sheets by a small angle changes the dynamics of switching thanks to the formation of moiré ferroelectricity with staggered polarization. The ferroelectricity persists to room temperature while keeping the high mobility of graphene, paving the way for potential ultrathin nonvolatile memory applications.

DOI: 10.1126/science.abd3230

Source: https://science.sciencemag.org/content/early/2021/05/26/science.abd3230