Defect-Induced Magnetic Skyrmion in Two-Dimensional Chromium Tri-Iodide Monolayer

Tailoring High-Frequency Magnonics in Monolayer Chromium Trihalides

Monolayer chromium trihalides, the archetypal two dimensional (2D) magnetic materials, are readily suggested as a promising platform for high frequency magnonics. Here we detail the spin wave properties of monolayer CrBr$_3$ and CrI$_3$, using spin dynamics simulations parametrized from the first principles. We reveal that spin wave dispersion can be tuned in a broad range of frequencies by strain, paving the way towards flexo magnonic applications. We further show that ever present halide vacancies in these monolayers host sufficiently strong Dzyaloshinskii Moriya interaction to scatter spin …

Uncovering A Two-Dimensional Semiconductor with Intrinsic Ferromagnetism at Room Temperature

Two-dimensional materials have been gaining great attention as they displayed a broad series of electronic properties that ranging from superconductivity to topology. Among them, those which possess magnetism are most desirable, enabling us to manipulate charge and spin simultaneously. Here, based on first-principles calculation, we demonstrate monolayer chromium iodide arsenide (CrIAs), an undiscovered stable two-dimensional material, is an intrinsic ferromagnetic semiconductor with out-of-plane spin magnetization. The indirect bandgaps are predicted to be 0.32 eV for majority spin and 3.31 e…

单层铬基三重Q磁体中的反常谷霍尔效应

Anomalous valley Hall effect in monolayer chromium-based triple-Q magnets

本文通过密度泛函理论预测单层铬基材料的三重Q磁绝缘基态，揭示其源于Cr 3d电子交换竞争，并在无自旋轨道耦合条件下发现巨大谷劈裂的反常谷霍尔效应，为谷电子学研究提供新方向。

Nonreciprocal Second-Harmonic Generation in Few-Layer Chromium Triiodide

It is of fundamental importance but challenging to simultaneously identify atomic and magnetic configurations of two-dimensional van der Waals materials. In this work, we show that the nonreciprocal second-harmonic generation (SHG) can be a powerful tool to answer this challenge. Despite the preserved lattice inversion symmetry, the interlayer antiferromagnetic order and spin-orbit coupling generate enhanced SHG in PT-symmetric bilayer chromium triiodide (CrI3). Importantly, the in-plane polarization-resolved SHG is sensitive to subtly different interlayer structures that cannot be told by lin…

稳定的二维单层三卤化铬的稳健内禀铁磁性和半导体性

Robust Intrinsic Ferromagnetism and Half Semiconductivity in Stable Two-Dimensional Single-Layer Chromium Trihalides

二维本征铁磁半导体是发展低维自旋电子器件的关键。利用密度泛函理论，我们证明了单层三卤化铬（CrX $_3$，X=F，Cl，Br和I）构成了一系列稳定的二维本征FM半导体.由于低的解理能和高的面内刚度，独立的SLCT可以容易地从块体晶体剥离。用HSE 06泛函方法计算的电子结构表明，体相和单层CrX $_3$都是具有间接带隙的半导体，它们的价带和导带在相同的自旋方向上完全自旋极化.发现CrBr $_3$和CrI $_3$的能隙和吸收边在可见光频率范围内，这意味着可能的光电子应用。此外，SLCT被发现具有每个分子式单元3 $μ_B$的大磁矩和相当大的磁各向异性能。利用海森堡自旋哈密顿量提取了SLCT的磁交换常数，并分析了各种交换相互作用的微观起源。近90 $^\circ$ FM超交换和直接反铁磁（AFM）交换之间的竞争导致FM最近邻交换相互作用。第二和第三近邻交换相互作用分别为FM和AFM，这可以用角度依赖的扩展Cr-X-X-Cr超交换相互作用来理解。此外，利用蒙特卡罗模拟还预测了SLCT的居里温度，并且通过施加双轴拉伸应变，可以进一步提高居里温度。强大的固有铁磁性，半磁导率和大的磁各向异性能量的独特组合，使SLCT作为下一代半导体自旋电子学应用的有前途的候选人。

Quasiparticle Energies and Excitonic Effects of Chromium Trichloride: from Two Dimensions to Bulk

Layered van der Waals (vdW) magnetic materials have attracted significant research interest to date. In this work, we employ the first-principles many-body perturbation theory to calculate excited-state properties of a prototype vdW magnet, chromium trichloride (CrCl3), covering monolayer, bilayer, and bulk structures. Unlike usual non-magnetic vdW semiconductors, in which many-electron interactions and excited states are sensitive to dimensionality, many-electron interactions are always enhanced and dominate quasiparticle energies and optical responses of both two-dimensional and bulk CrCl3. …