论文标题
（fe $ _ {1-x} $ ni $ _ {x} $）$ _ {5} $ gete $ _ {2} $：一种反铁磁性三角形的iSing iSing lattice，带有流行磁性
(Fe$_{1-x}$Ni$_{x}$)$_{5}$GeTe$_{2}$: an antiferromagnetic triangular Ising lattice with itinerant magnetism
论文作者
论文摘要
根据第一原则的计算，已经提出了一种三角晶格上的抗铁磁性模型来解释fe $（1）$ - ge对的顺序和$ \ sqrt {3} $ \ times $ \ times $ $ $ $ $ $ $ $ \ \ \ sqrt {3} $ supperstructures在fe $ _5 $ _5 $ _5 $ _5 $ _5 $ _5 $ _5 $ _5在Ni掺杂的F5GT（Ni-F5GT）中存在类似的上层建筑。我们的研究表明，F5GT系统可以被视为三角形晶格上众所周知的抗铁磁ising模型的结构实现。根据上层建筑的基于Heisenberg-Landau Hamiltonian，考虑到了海森堡的相互作用和纵向旋转波动，以描述F5GT和Ni-F5GT中的磁性。我们公布了与Fe（1）相关的沮丧的磁相互作用，该磁相互作用是由微小的Ni掺杂（$ x \ leq 0.2 $）调节的，负责实验观察到的Ni-F5GT中的$ T_C $至478 K的增强。我们的计算表明，在低掺杂水平下，单层Ni-F5GT的磁相图几乎与散装相同，这表明在此NI掺杂的二维系统中，室温超出了室温超出室温超出室温。
Based on first-principles calculations, an antiferromagnetic Ising model on a triangular lattice has been proposed to interpret the order of Fe$(1)$-Ge pairs and the formation of $\sqrt{3}$ $\times $ $\sqrt{3}$ superstructures in the Fe$_5$GeTe$_2$ (F5GT), as well as to predict the existence of similar superstructures in Ni doped F5GT (Ni-F5GT). Our study suggests that F5GT systems may be considered as a structural realization of the well known antiferromagnetic Ising model on a triangular lattice. Based on the superstructures, a Heisenberg-Landau Hamiltonian, taking into account both Heisenberg interactions and longitudinal spin fluctuations, is implemented to describe magnetism in both F5GT and Ni-F5GT. We unveil that frustrated magnetic interactions associated with Fe(1), tuned by a tiny Ni doping ($x \leq 0.2 $), is responsible for the experimentally observed enhancement of the $T_c$ to 478 K in Ni-F5GT. Our calculations show that at low doping levels, monolayer Ni-F5GT has almost the same magnetic phase diagram as that of the bulk, which indicates a pervasive beyond room temperature ferromagnetism in this Ni doped two-dimensional system.
