论文标题
二维稀土卤化物单相三必须
Two-dimensional Rare-earth Halide Based Single Phase Triferroic
论文作者
论文摘要
由于其在纳米电子和自旋设备中应用的巨大潜力，二维多性材料受到了极大的追捧。我们在这里预测，基于第一原则计算，一个单相{\ it三氟}，其中三个铁阶；铁电磁，铁电和铁弹性同时在掺杂的gdcl $ _2 $单层（铁磁半导体）中同时共存。这是通过将gd $^{2+} $的GD $^{2+} $离子替换为GDCL $ _2 $单层的Hexagonal结构中的1/3 $^{2+} $ ions来实现的。所得的金属状态经历以键为中心的荷式订购，以驱动六边形结构中的失真，使其再次半导体和{\ it Ferroalastic}。此外，晶格失真伴随着晶格中心对称性的破坏，使非中心对称电荷分布使单层{\ it铁电}同时使单层。欧盟掺杂的GDCL $ _2 $单层中存在的两个Froic订单，即铁电和铁弹性，这是强烈耦合的，这使其成为设备应用的有前途的候选人。掺杂的单层仍然像母体单层一样具有大4F磁矩的铁磁半导体，并且比其原始磁性磁力（MAE）具有更高的（平面外）磁动率能量（MAE），其原始的对应物需要二维磁体具有较高的过渡温度。
Two-dimensional multiferroic materials are highly sought after due to their huge potential for applications in nanoelectronic and spintronic devices. Here, we predict, based on first-principle calculations, a single phase {\it triferroic} where three ferroic orders; ferromagnetism, ferroelectricity and ferroelasticity, coexist simultaneously in hole doped GdCl$_2$ monolayer (a ferromagnetic semiconductor). This is achieved by substituting 1/3rd of the Gd$^{2+}$ ions with Eu$^{2+}$ in the hexagonal structure of GdCl$_2$ monolayer. The resulting metallic state undergoes a bond-centered charge ordering driving a distortion in the hexagonal structure making it semiconducting again and {\it ferroelastic}. Further, the lattice distortion accompanied by a breaking of the lattice centrosymmetry renders a non-centrosymmetric charge distribution which makes the monolayer {\it ferroelectric}, at the same time. The two ferroic orders, ferroelectricity and ferroelasticity, present in Eu doped GdCl$_2$ monolayer are found to be strongly coupled making it a promising candidate for device applications. The doped monolayer remains a ferromagnetic semiconductor with large 4f magnetic moment just like the parent monolayer and possesses an even higher (out-of-plane) magnetic anisotropy energy (MAE) than its pristine counterpart as desired for two dimensional magnets to have high transition temperature.
