反Lieb晶格交替磁体中的多轨道物理
Multi-orbital physics in inverse Lieb lattice altermagnets
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中文总结 AI 辅助
本文构建含子晶格与轨道自由度的微观哈密顿量，研究钒氧硫族化物交替磁体的多轨道物理，发现xy轨道稳定交替磁态、xz/yz轨道序由洪德耦合诱导，且存在轨道选择性拓扑边缘态。
中文摘要 AI 辅助
反Lieb晶格近来成为极具潜力的交替磁体研究平台，已有多种该结构的材料被提出作为d波交替磁候选材料。本文针对这类材料构建了基于对称性的微观哈密顿量，包含子晶格与轨道自由度，突破了此前广泛用于此类交替磁体研究的仅含子晶格的最小模型。将该模型应用于钒氧硫族化物家族交替磁体，该类材料在交替磁态的费米能级处具有主导的xy和xz/yz轨道特征。研究表明，xy轨道对稳定单个V₂O层内观测到的交替磁态至关重要，而xz/yz轨道的交替磁序通过洪德耦合诱导；此外，这类多轨道模型揭示了拓扑 regime，其中拓扑边缘态具有天然的轨道选择性。
英文摘要
The inverse Lieb lattice has recently emerged as a promising platform for altermagnetism, with several materials with this structure proposed as $d$-wave altermagnetic candidates. Here, we develop a symmetry-based microscopic Hamiltonian for these materials that includes both sublattice and orbital degrees of freedom, going beyond the sublattice-only minimal models that have been extensively used to study such altermagnets. We apply these models to examine multi-orbital electron correlation physics in the vanadium oxychalcogenide family altermagnets, which contain dominant $xy$ and $xz/yz$ orbitals character at the Fermi level in the altermagnetic state. We demonstrate that $xy$ orbitals are crucial to stabilize the altermagnetic state observed within a single V$_2$O layer, and altermagnetic order in the $xz/yz$ orbitals is induced through Hund's coupling. Additionally, we show that these multi-orbital models reveal topological regimes in which topological edge states are naturally orbital selective.
