二维交错磁铬硫属化物中的拓扑自旋织构：磁阻挫与Dzyaloshinskii-Moriya相互作用的交织
Topological spin textures in 2D altermagnetic chromium chalcogenides: Interplay between magnetic frustration and Dzyaloshinskii-Moriya interaction
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中文总结 AI 辅助
本研究通过第一性原理和自旋模拟，揭示二维交错磁体Cr2X2和Janus Cr2XY中磁阻挫与DMI的协同及竞争机制，为设计拓扑自旋织构提供通用框架。
中文摘要 AI 辅助
交错磁最近作为一种独特的磁性范式出现，然而二维（2D）交错磁体中拓扑自旋织构的探索仍然有限。利用第一性原理计算和原子级自旋模拟，我们研究了单层Cr2X2和Janus单层Cr2XY交错磁体（X, Y = O, S, Se, Te，且X ≠ Y）。两种体系都表现出由最近邻和次近邻交换相互作用竞争引起的强本征交换阻挫。在Janus Cr2XY中，破坏面外镜面对称性还额外激活了由重硫属配体的强自旋轨道耦合介导的显著面内Dzyaloshinskii-Moriya相互作用（DMI）。交换阻挫与DMI之间的交织产生了不同的阻挫主导和DMI主导区域，而磁各向异性决定了优先自旋取向，导致多种非共线态。系统的相空间扫描和测地线微移弹性带（GNEB）计算揭示了控制这种交织的两种不同机制：协同效应，其中阻挫降低了非共线态起始的临界DMI；以及竞争效应，其中阻挫有利于高拓扑荷态，而DMI有利于低荷态。我们的结果为理解阻挫与DMI之间的交织以及指导二维交错磁体中拓扑自旋织构的设计建立了一个通用框架。
英文摘要
Altermagnetism has recently emerged as a distinct magnetic paradigm, yet the exploration of topological spin textures within two-dimensional (2D) altermagnets remains limited. Using first-principles calculations and atomistic spin simulations, we investigate monolayer $\mathrm{Cr_2X_2}$ and Janus monolayer $\mathrm{Cr_2XY}$ altermagnets ($\mathrm{X, Y}=\mathrm{O, S, Se, Te}$, and $\mathrm{X \neq Y}$). Both systems exhibit strong intrinsic exchange frustration arising from competition between nearest-neighbor and further-neighbor exchange interactions. In Janus $\mathrm{Cr_2XY}$, breaking the out-of-plane mirror symmetry additionally activates a substantial in-plane Dzyaloshinskii-Moriya interaction (DMI), mediated by the strong spin-orbit coupling of heavy chalcogen ligands. The interplay between exchange frustration and DMI gives rise to distinct frustration- and DMI-dominated regimes, while magnetic anisotropy determines the preferred spin orientation, leading to a diverse range of non-collinear states. Systematic phase-space scans and geodesic nudged elastic band (GNEB) calculations reveal two distinct mechanisms governing this interplay: a synergistic effect, in which frustration lowers the critical DMI for the onset of non-collinear states, and a competitive effect, in which frustration favors high-topological-charge states while DMI favors low-charge states. Our results establish a general framework for understanding the interplay between frustration and DMI and guiding the design of topological spin textures in two-dimensional altermagnets.
发表机构
- Zhejiang Sci-Tech University（浙江理工大学）
- Zhejiang Key Laboratory of Quantum State Control and Optical Field Manipulation, Zhejiang Sci-Tech University（浙江量子态调控与光场操控重点实验室）
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