论文标题
二维金属铁磁铁Fe $ _3 $ gete $ _2 $
Large magneto-optical effect and magnetic anisotropy energy in two-dimensional metallic ferromagnet Fe$_3$GeTe$_2$
论文作者
论文摘要
很少有Fe $ _3 $ gete $ _2 $是目前唯一的薄铁磁金属，因此在二维（2D）磁性领域引起了极大的关注。在本文中，我们对单层（ML），BiLayer（BL）和Trilayer（TL）以及Bulk Fe $ _3 $ Gete $ _2 $ $ _2 $ $ _2 $进行了有关电子结构，磁各向异性能量（MAE）和磁光（MO）效应的系统第一主要研究。预计所有考虑的Fe $ _3 $ gete $ _2 $的结构都具有很大的订单$ \ sim $ 3.0 mev/f.u。，比报道的2D铁磁半导体Cr $ _2 $ _2 $ ge $ _2 $ ge $ _2 $ _2 $ _2 $ _2 $ _6 $ _6 $和cri $ _3 $，以及与fept y mae相比，这是一个很大的差异。因此，这个大型的MAE将远程铁磁订单稳定在原子上薄层上，还提出了2d Fe $ _3 $ gete $ _2 $在高密度数据存储中的有希望的应用。此外，计算出的磁光谱显示出较大的磁性圆形二色性，从而导致较大的mo kerr旋转和法拉第旋转角度。在可见的频率范围内，发现了tl fe $ _3 $ gete $ _2 $的kerr旋转角度最高$ \ sim $ \ sim $ 1.0 $^\ circ $。此类值大于著名的MO过渡金属合金MNBI。此外，预测所有被认为是Fe $ _3 $ gete $ _2 $结构的大型法拉第旋转角度。特别是，ML Fe $ _3 $ gete $ _2 $具有-156 $^\ circ $/$μm$的法拉第旋转角度，其比著名的Mo氧化物BI $ _3 $ _3 $ _5 $ _5 $ _5 $ o $ $ _ {12} $大三倍。这些重要的发现是根据计算出的状态轨道密度和偶极选择规则的分析。因此，我们的发现表明，很少有层和大量Fe $ _3 $ gete $ _2 $是有希望的Mo材料，将来可以广泛应用于Nano Mo设备。
Few layers Fe$_3$GeTe$_2$ is currently the only atomically thin ferromagnetic metal, and thus has drawn huge attention in the field of two-dimensional (2D) magnetism. In this paper, we perform a systematic first principle study on the electronic structure, magnetic anisotropy energy (MAE), and magneto-optical (MO) effects in monolayer (ML), bilayer (BL) and trilayer (TL) as well as bulk Fe$_3$GeTe$_2$. All the considered structures of Fe$_3$GeTe$_2$ are predicted to have large MAE of order $\sim$3.0 meV/f.u., being larger than reported 2D ferromagnetic semiconductors Cr$_2$Ge$_2$Te$_6$ and CrI$_3$ and also being comparable to that of FePt which has the largest MAE among the transition metal alloys. This large MAE thus stabilizes the long range ferromagnetic order down to atomically thin layers and also suggests promising applications of 2D Fe$_3$GeTe$_2$ in high density data storage. Furthermore, the calculated magneto-optical spectra show large magnetic circular dichroism, thus resulting in large MO Kerr rotation and Faraday rotation angles. In visible frequency range, Kerr rotation angles up to $\sim$1.0$^\circ$ for TL Fe$_3$GeTe$_2$ are found. Such values are larger than famous MO transition metal alloy MnBi. Also, large Faraday rotation angles are predicted for all considered Fe$_3$GeTe$_2$ structures. In particular, ML Fe$_3$GeTe$_2$ has a Faraday rotation angle of -156$^\circ$/$μm$, which is three times larger than famous MO oxide Bi$_3$Fe$_5$O$_{12}$. These important findings are analysed in terms of the calculated orbital-decomposed density of states and dipole selection rule derived from the group theory. Our findings thus suggest that few layers and bulk Fe$_3$GeTe$_2$ are promising MO materials and could be widely applied to nano MO devices in the future.
