发表机构
Loughborough University; Leibniz IFW Dresden; University of Leipzig（勒伯勒大学; 莱布尼茨德累斯顿固体研究所; 莱比锡大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
研究预测的交替磁体CuF₂，发现其磁子能带分裂源于强Dzyaloshinskii-Moriya相互作用而非交替磁性，揭示了3d磁体中相对论效应的重要性。
AI 中文摘要
交替磁性态的确定不能仅依赖对称性论证，本文通过对金红石类材料CuF₂的计算与实验结合研究对此进行了说明，CuF₂属于预测的交替磁体列表。利用从头算、线性自旋波计算及磁化测量，我们表明实验单斜结构的CuF₂可描述为弱耦合平方晶格层的自旋-1/2模型，面内耦合J₁≈115 K，两个协同的层间反铁磁耦合分别为J₁的4%和8%。这些层间耦合由长程超交换驱动，相对于平方平面倾斜，导致磁有序态下晶胞加倍，从而有效抑制了任何交替磁性能带分裂。同时，我们识别出异常强的Dzyaloshinskii-Moriya相互作用，|D|/J₁≈0.3，其产生自旋倾斜，并与有序-无序效应一起将奈尔矢量钉扎到晶体学b轴。此外，DM各向异性促进磁子能带分裂，但这些能带仍为非手性。我们的结果强调了相对论效应在具有交替磁性对称性的3d磁体中的重要性。
英文摘要
Conclusive identification of an altermagnetic state requires going beyond mere symmetry arguments. We illustrate this in a combined computational and experimental study of the rutile-like material CuF$_2$, which is on the list of predicted altermagnets. Using ab initio and linear spin-wave calculations supplied by magnetization measurements, we show that CuF$_2$ in its experimental monoclinic structure can be described by a spin-$\frac12$ model of weakly coupled square-lattice layers with the in-plane coupling $J_1\simeq 115$ K and two synergistic antiferromagnetic interplane couplings amounting to 4% and 8% of $J_1$, respectively. Driven by long-range superexchange, these interlayer couplings are oblique to the square planes, resulting in the unit-cell doubling in the magnetically ordered state, thus effectively suppressing any altermagnetic band splitting. Concurrently, we identify unusually strong Dzyaloshinskii-Moriya interactions, $|\mathbf D|/J_1\simeq 0.3$, that produce spin canting and, together with order-by-disorder effect, pin the Néel vector to the crystallographic $b$-axis. Additionally, DM anisotropy promotes magnon band splitting, but these bands remain non-chiral. Our results highlight the importance of relativistic effects even in $3d$ magnets with altermagnetic symmetries.
Comments10 pages, 7 figures (+10 pages Supplementing material)
