Lyu Hou-Yi, Zhang Zhen, You Jing-Yang, Yan Qing-Bo, Su Gang
Center of Materials Science and Optoelectronics Engineering, College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing100049, China.
Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Division of Advanced Materials, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123China.
J Phys Chem Lett. 2022 Dec 15;13(49):11405-11412. doi: 10.1021/acs.jpclett.2c03169. Epub 2022 Dec 2.
Intrinsic two-dimensional (2D) multiferroics that couple ferromagnetism and ferroelectricity are rare. Here, we present an approach to achieve 2D multiferroics using powerful intercalation technology. In this approach, metal atoms such as Cu or Ag atoms are intercalated in bilayer CrI to form Cu(CrI) or Ag(CrI). The intercalant leads to the inversion symmetry breaking and produces a large out-of-plane electric polarization with a low transition barrier and a small reversal electric field, exhibiting excellent 2D ferroelectric properties. In addition, due to charge transfer between the intercalated atoms and bilayer CrI, the interlayer coupling transits from antiferromagnetic to ferromagnetic, and the intralayer ferromagnetic coupling is also enhanced. Furthermore, the built-in electric polarization causes a distinct surface magnetization difference, generating a strong magnetoelectric coupling with a coefficient larger than that of Fe, Co, and Ni thin films. Our work paves a practical path for 2D multiferroics, which may have crucial applications in spintronics.
将铁磁性和铁电性耦合在一起的本征二维（2D）多铁性材料十分罕见。在此，我们展示了一种利用强大的插层技术实现二维多铁性材料的方法。在这种方法中，诸如铜或银原子等金属原子被插入双层CrI中以形成Cu（CrI）或Ag（CrI）。插层剂导致反演对称性破缺，并产生具有低转变势垒和小反向电场的大的面外极化，展现出优异的二维铁电特性。此外，由于插层原子与双层CrI之间的电荷转移，层间耦合从反铁磁转变为铁磁，并且层内铁磁耦合也得到增强。此外，内建极化导致明显的表面磁化差异，产生比铁、钴和镍薄膜的系数更大的强磁电耦合。我们的工作为二维多铁性材料开辟了一条实用途径，其可能在自旋电子学中具有关键应用。
