Yu Cuiju, Cheng Jing, Zhang Yuzhuo, Liu Zhao, Liu Xiaofeng, Jia Chao, Li Xingxing, Yang Jinlong
Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
Key Laboratory of Precision and Intelligent Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China.
J Phys Chem Lett. 2024 Apr 18;15(15):4218-4223. doi: 10.1021/acs.jpclett.4c00524. Epub 2024 Apr 11.
Two-dimensional (2D) ferroelectric metals (FEMs) possess intriguing characteristics, such as unconventional superconductivity and the nonlinear anomalous Hall effect. However, their occurrence is exceedingly rare due to mutual repulsion between ferroelectricity and metallicity. In addition, further incorporating other features like ferromagnetism into FEMs to enhance their functionalities poses a significantly greater challenge. Here, via first-principles calculations, we demonstrate a case of an FEM that features a coexistence of room-temperature ferromagnetism, ferroelectricity, and metallicity in a thermodynamically stable 2D OsSe. It presents a vertical electric polarization of 3.00 pC/m that exceeds those of most FEMs and a moderate polarization switching barrier of 0.22 eV per formula unit. Moreover, 2D OsSe exhibits robust ferromagnetism (Curie temperature ≈ 527 K) and a sizable magnetic anisotropy energy (-30.87 meV per formula unit). Furthermore, highly magnetization-dependent electrical conductivity is revealed, indicative of strong magnetoelectric coupling. Berry curvature calculation suggests that the FEM might exhibit nontrivial band topology.
二维（2D）铁电金属（FEMs）具有诸如非常规超导性和非线性反常霍尔效应等引人入胜的特性。然而，由于铁电性和金属性之间的相互排斥，它们的出现极为罕见。此外，进一步将诸如铁磁性等其他特性纳入FEMs以增强其功能带来了更大得多的挑战。在此，通过第一性原理计算，我们展示了一个FEM的例子，即在热力学稳定的二维OsSe中存在室温铁磁性、铁电性和金属性的共存。它呈现出3.00 pC/m的垂直电极化，超过了大多数FEMs的电极化，并且每个化学式单位具有0.22 eV的适度极化切换势垒。此外，二维OsSe表现出强铁磁性（居里温度≈527 K）和相当大的磁各向异性能量（每个化学式单位-30.87 meV）。此外，还揭示了高度依赖磁化的电导率，表明存在强磁电耦合。贝里曲率计算表明，该FEM可能表现出非平凡的能带拓扑结构。
