发表机构
Christian-Albrechts-Universität zu Kiel; Kiel Nano, Surface, and Interface Science (KiNSIS), University of Kiel（基尔大学; 基尔大学纳米、表面与界面科学研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文采用第一性原理电子结构理论，以Pd/Mn双层膜等为模型体系，对比RW-AFM态与3Q态，区分轨道磁矩的拓扑与自旋-轨道贡献，发现自旋补偿体系中TOMs有重要贡献，原子级斯格明子晶格计算也验证该趋势。
AI 中文摘要
拓扑轨道磁矩（TOMs）是具有非平凡自旋拓扑的磁性织构的直接标志。除了能为磁性织构的拓扑性质提供深入见解外，TOMs还可用于操控总自旋磁矩补偿的磁性结构。插层范德华材料的霍尔效应输运测量已为TOMs提供了实验证据，但TOMs的直接观测仍未实现。另一难点在于对拓扑起源的明确验证，因为轨道磁矩也可能由自旋-轨道耦合产生。本文中，我们采用第一性原理电子结构理论，研究不同具有非平凡拓扑的自旋补偿结构中轨道磁矩的起源。我们聚焦于表面的超薄磁性薄膜，如Re(0001)上的Pd/Mn双层膜，该体系是检测TOMs的理想模型系统，因为可采用具有磁性局部分辨率的实验技术，如自旋极化扫描隧道显微镜。由于其拓扑平凡，我们采用六角单层的行式反铁磁（RW-AFM）态来分析自旋-轨道诱导的贡献。三重Q（3Q）态是三个RW-AFM（1Q）态的叠加态，电子结构与RW-AFM态相似，但由于其非平凡自旋拓扑，它表现出TOMs。通过对比这两种自旋态，我们可区分轨道磁矩的拓扑贡献与自旋-轨道贡献。我们发现，在自旋补偿体系中，TOMs具有重要贡献，因为自旋-轨道耦合诱导的轨道磁矩几乎被补偿。对不同表面上Fe单层的原子级斯格明子晶格的第一性原理计算，展现出与3Q态相同的普遍趋势。
英文摘要
Topological orbital moments (TOMs) are a direct hallmark of a magnetic texture with a non-trivial spin topology. In addition to giving insight into the topology of the magnetic texture, TOMs could also be used to manipulate magnetic structures with a compensated total spin moment. Experimental evidence of TOMs has been provided via transport measurements of the Hall effect in intercalated van-der-Waals materials. However, a direct observation of TOMs is still missing. Another complication arises for the unambiguous proof of the topological origin since orbital moments can also occur due to spin-orbit coupling. Here, we use first-principles electronic structure theory to investigate the origin of orbital moments in different compensated spin structures with a non-trivial topology. We focus on ultrathin magnetic films at surfaces such as Pd/Mn bilayers on Re(0001) which represent ideal model systems for the detection of TOMs since it is possible to apply experimental techniques with local resolution of magnetic properties such as spin-polarized scanning tunneling microscopy. Due to its trivial topology we use the row-wise antiferromagnetic (RW-AFM) state in a hexagonal monolayer to analyze the spin-orbit induced contributions. The triple-Q (3Q) state is a superposition state of three RW-AFM (1Q) states and thus electronically similar, however, due to its non-trivial spin topology it exhibits TOMs. The comparison between these two spin states allows us to disentangle the topological and spin-orbit contributions to the orbital moments. We find that TOMs have an important contribution in spin-compensated systems, since the spin-orbit coupling induced orbital moments are nearly compensated. First-principles calculations for atomic-scale skyrmion lattices in Fe monolayers on different surfaces exhibit the same general trend found for the 3Q state.
