Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), Dalian University of Technology, Dalian116024, China.
J Phys Chem Lett. 2022 Dec 8;13(48):11346-11353. doi: 10.1021/acs.jpclett.2c03160. Epub 2022 Dec 1.
Two-dimensional (2D) intrinsic multiferroics have long been pursued not only for their potential technological applications but also as model systems for studying emergent quantum phenomena and coupling mechanisms between various order parameters in low-dimensional space. However, the realization of 2D multiferroics is still a challenge. In this paper, we reveal that 2D AgCrX (X = S or Se) crystals, which have been synthesized from the non-van der Waals (non-vdW) AgCrX bulk phase, are type I half-metallic/metallic multiferroics in which ferroelectricity and ferromagnetism coexist. The off-centering displacement of the Ag ion introduces out-of-plane polarization, and the magnetism originates from the interactions between Cr atoms. Remarkably, AgCrSe shows topologically nontrivial spin textures, such as Meron pairs and Néel-type skyrmions, under suitable temperatures and magnetic fields. Our findings demonstrate that 2D multiferroics can be achieved from non-vdW materials and in turn open a new avenue for 2D multiferroics.
二维(2D)本征多铁体不仅因其潜在的技术应用而备受关注,还因其在低维空间中研究新兴量子现象和各种序参量之间耦合机制的模型体系而备受关注。然而,二维多铁体的实现仍然是一个挑战。在本文中,我们揭示了从非范德华(非 vdW)AgCrX 体相中合成的 2D AgCrX(X = S 或 Se)晶体是一类共存铁电性和铁磁性的Ⅰ型半金属/金属多铁体。Ag 离子的非中心位移引入了面外极化,而磁性则源于 Cr 原子之间的相互作用。值得注意的是,AgCrSe 在适当的温度和磁场下表现出拓扑非平凡的自旋纹理,如 Meron 对和 Neel 型 skyrmions。我们的发现表明可以从非 vdW 材料中获得二维多铁体,并为二维多铁体开辟了新的途径。