Yang Yali, Ji Junyi, Feng Junsheng, Chen Shiyou, Bellaiche Laurent, Xiang Hongjun
Key Laboratory of Computational Physical Sciences (Ministry of Education), Institute of Computational Physical Sciences, and Department of Physics, Fudan University, Shanghai 200433, China.
Shanghai Qi Zhi Institute, Shanghai 200030, China.
J Am Chem Soc. 2022 Aug 17;144(32):14907-14914. doi: 10.1021/jacs.2c06347. Epub 2022 Aug 4.
Organic-inorganic multiferroics are promising for the next generation of electronic devices. To date, dozens of organic-inorganic multiferroics have been reported; however, most of them show a magnetic Curie temperature much lower than room temperature, which drastically hampers their application. Here, by performing first-principles calculations and building effective model Hamiltonians, we reveal a molecular orbital-mediated magnetic coupling mechanism in two-dimensional Cr(pyz) (pyz = pyrazine) and the role that the valence state of the molecule plays in determining the magnetic coupling type between metal ions. Based on these, we demonstrate that a two-dimensional organic-inorganic room-temperature multiferroic, Cr(h-fpyz) (h-fpyz = half-fluoropyrazine), can be rationally designed by introducing ferroelectricity in Cr(pyz) while keeping the valence state of the molecule unchanged. Our work not only reveals the origin of magnetic coupling in 2D organic-inorganic systems but also provides a way to design room-temperature multiferroic materials rationally.
有机-无机多铁性材料在下一代电子器件方面具有广阔前景。迄今为止，已有数十种有机-无机多铁性材料被报道；然而，它们中的大多数显示出的磁居里温度远低于室温，这极大地阻碍了它们的应用。在此，通过进行第一性原理计算并构建有效的模型哈密顿量，我们揭示了二维Cr(pyz)（pyz = 吡嗪）中一种分子轨道介导的磁耦合机制以及该分子的价态在确定金属离子间磁耦合类型中所起的作用。基于这些，我们证明了一种二维有机-无机室温多铁性材料Cr(h-fpyz)（h-fpyz = 半氟吡嗪）可以通过在Cr(pyz)中引入铁电性同时保持分子的价态不变而合理设计出来。我们的工作不仅揭示了二维有机-无机体系中磁耦合的起源，还提供了一种合理设计室温多铁性材料的方法。
