碱金属掺杂CrI$_3$中的二元磁性与定向磁振子输运
Binary magnetism and directional magnon transport in alkali-doped CrI$_3$
- University of Antwerp（安特卫普大学）
- Universidade Federal de Pernambuco（伯南布哥联邦大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究通过碱金属掺杂单层CrI$_3$，发现其诱导二元磁矩与非共线磁序，并产生各向异性及非互易的磁振子输运，为调控二维磁体的磁振子性质提供了新途径。
AI中文摘要：
二维（2D）磁体的近期实现，以CrI$_3$为先驱范例，为二维材料和磁性领域开辟了新途径。这一突破之后，人们进行了大量努力来操控和利用其磁性质。在本工作中，我们研究了碱金属原子的吸附作为调控单层CrI$_3$磁行为的一种途径。我们表明，吸附后，碱金属原子向CrI$_3$层捐赠一个电子，导致形成不等价的Cr位点，其中一个Cr原子表现出增强的磁矩$4~\mu_B$，而另一个则保持其典型的$3~\mu_B$磁矩。这些修饰显著改变了磁交换相互作用，包括各向异性交换和Dzyaloshinskii--Moriya相互作用（DMI）的出现。因此，掺杂体系表现出非共线磁基态、修正的温度依赖性磁性和各向异性的自旋波传播，其优先传播方向随着掺杂剂尺寸的增大而日益显著。此外，观察到自旋波在相反方向传播的不对称性，产生了类似二极管的效果，特别是对于较重的掺杂剂。这种行为归因于增强的DMI，它打破了磁振子色散的对称性。这些结果表明，碱金属掺杂为调控二维磁性材料中的各向异性和非互易磁振子性质提供了一条有效途径。
英文摘要：
The recent realization of two-dimensional (2D) magnets, with CrI$_3$ as a pioneering example, has opened new avenues in the fields of 2D materials and magnetism. This breakthrough has been followed by extensive efforts to manipulate and exploit their magnetic properties. In this work, we investigate the adsorption of alkali-metal atoms as a route to control the magnetic behavior of monolayer CrI$_3$. We show that, upon adsorption, alkali-metal atoms donate an electron to the CrI$_3$ layer, leading to the formation of inequivalent Cr sites, with one Cr atom exhibiting an enhanced magnetic moment of $4~μ_B$, while the other retains its typical $3~μ_B$ moment. These modifications significantly alter the magnetic exchange interactions, including the emergence of anisotropic exchange and Dzyaloshinskii--Moriya interactions (DMI). Consequently, the doped systems exhibit non-collinear magnetic ground states, modified temperature-dependent magnetism, and anisotropic spin-wave propagation, with a preferred propagation direction that becomes increasingly pronounced with increasing dopant size. Furthermore, an asymmetry between spin-wave propagation in opposite directions is observed, giving rise to a diode-like effect, particularly for heavier dopants. This behavior is attributed to the enhanced DMI, which breaks the symmetry of the magnon dispersion. These results demonstrate that alkali-metal doping provides an effective route to tune anisotropic and nonreciprocal magnonic properties in two-dimensional magnetic materials.
