通过畸变从Kitaev自旋链到XXZ自旋链的演化：应用于BaCo₂V₂O₈

中文摘要 AI 辅助

BaCo₂V₂O₈是一种典型的自旋轨道耦合伊辛链反铁磁体，为研究场诱导量子磁性提供了独特平台。在横向磁场下，它展现出异常磁性，包括反常交错磁化强度，以及临界场相对于面内磁场方向的显著各向异性。这些现象曾从唯象角度归因于位置依赖的各向异性g张量，而近期微观理论表明，自旋轨道耦合会自然产生依赖键的海森堡、Kitaev和Γ交换相互作用。本文通过扩展微观理论以纳入CoO₆八面体的畸变，将上述两种图景统一起来。研究表明，畸变不仅会产生位置依赖的各向异性g张量，还会通过畸变诱导的贡献重整化交错交换相互作用，该贡献会部分补偿Kitaev衍生的交错项。利用点电荷计算估算BaCo₂V₂O₈的g张量，本文证明临界场的强各向异性源于修正后的交换相互作用与各向异性g张量的共同作用。本研究为理解自旋轨道耦合伊辛链材料的磁各向异性提供了统一的微观框架。

英文摘要

BaCo$_2$V$_2$O$_8$ is a prototypical spin-orbit-coupled Ising-chain antiferromagnet that provides a unique platform for studying field-induced quantum magnetism. Under a transverse magnetic field, it exhibits unusual magnetic properties, including an anomalous staggered magnetization and a pronounced anisotropy of the critical field with respect to the in-plane field direction. While these phenomena have been attributed phenomenologically to a site-dependent anisotropic $g$-tensor, a recent microscopic theory has shown that spin-orbit coupling naturally generates bond-dependent Heisenberg, Kitaev, and $Γ$ exchange interactions. Here, we unify these two pictures by extending the microscopic theory to incorporate distortions of the CoO$_6$ octahedra. We show that the distortions not only generate the site-dependent anisotropic $g$-tensor but also renormalize the staggered exchange interactions through a distortion-induced contribution that partially compensates the Kitaev-derived staggered term. Using point-charge calculations to estimate the $g$-tensor of BaCo$_2$V$_2$O$_8$, we demonstrate that the strong anisotropy of the critical field originates from the combined effects of the modified exchange interactions and the anisotropic $g$-tensor. Our work provides a unified microscopic framework for understanding the magnetic anisotropy of spin-orbit-coupled Ising-chain materials.

发表机构

• University of Toronto（多伦多大学）
• Canadian Institute for Advanced Research（加拿大高级研究院）

机构由 AI 辅助整理，请以论文原文为准。

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9 pages, 4 figures