厘清Ba$_2$MgReO$_6$中的结构序、磁偶极序与电荷多极序
Untangling the structural, magnetic dipole, and charge multipolar orders in Ba$_2$MgReO$_6$
AI总结：
本文利用密度泛函理论研究Ba$_2$MgReO$_6$，证实并发现新的电荷四极序分量，揭示结构畸变与磁偶极取向对电荷四极序的必要作用，建立了结构—磁偶极—电荷多极关系。
摘要：
我们对双钙钛矿Ba$_2$MgReO$_6$的低温结构、磁性以及所提出的电荷四极序进行了密度泛函理论研究。Ba$_2$MgReO$_6$是一种自旋轨道驱动的Mott绝缘体，在33 K处发生对称性降低的结构相变，并在18 K处形成5$d^1$ Re磁矩的倾斜反铁磁序。我们的计算证实了所提出的电荷四极序的存在，并发现了一个此前被隐藏的额外有序电荷四极分量。通过分别隔离结构畸变和磁偶极取向，我们确定了电荷四极序、结构序和磁序之间的关系，发现要降低对称性并允许电荷四极存在，需要局域结构畸变或特定的磁偶极取向。我们的工作确立了Ba$_2$MgReO$_6$及相关5$d^1$双钙钛矿中晶体结构—磁偶极—电荷多极的关系，并展示了一种在通常偶极层次之外分离和分析结构、磁性与电荷序的贡献及相互作用的方法。
英文摘要：
We present a density functional theory study of the low-temperature structural, magnetic, and proposed charge-quadrupolar ordering in the double perovskite, Ba$_2$MgReO$_6$. Ba$_2$MgReO$_6$ is a spin-orbit-driven Mott insulator with a symmetry-lowering structural phase transition at 33\,K and a canted antiferromagnetic ordering of $5d^1$ Re magnetic moments at 18\,K. Our calculations confirm the existence of the proposed charge quadrupolar order and discover an additional, previously hidden, ordered charge quadrupolar component. By separately isolating the structural distortions and the orientations of the magnetic dipoles, we determine the relationship between the charge quadrupolar, structural and magnetic orders, finding that either a local structural distortion or a specific magnetic dipole orientation is required to lower the symmetry and enable the existence of charge quadrupoles. Our work establishes the crystal structure -- magnetic dipole -- charge multipole relationship in Ba$_2$MgReO$_6$ and related 5$d^1$ double perovskites, and illustrates a method for separating and analyzing the contributions and interactions of structural, magnetic, and charge orders beyond the usual dipole level.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
