论文标题

$ a $ v $ _3 $ sb $ _5 $ kagome金属的环路电流:多极和环形磁性订单

Loop currents in $A$V$_3$Sb$_5$ kagome metals: multipolar and toroidal magnetic orders

论文作者

Christensen, Morten H., Birol, Turan, Andersen, Brian M., Fernandes, Rafael M.

论文摘要

最近发现的基于钒的kagome金属的实验表明,他们的充电状态不仅显示键变形,也显示``真实的''电荷密度波(RCDW)的特征,而且还显示出``真实的''电荷扭曲(RCDW),而且还显示了``真实的''电荷对称性对称性,也通过`````''在这里,我们结合了密度功能理论,群体理论和现象学建模,以研究由$ a $ a $ v $ _3 $ _3 $ sb $ _5 $的电子结构中存在的低能量范霍夫奇异性之间的相互作用引起的复杂电荷订购状态。我们找到两类混合ICDW-RCDW配置:三重 - $ \ MathBf {q} $ ICDW,triple-$ \ Mathbf {q} $ rcdw订单,配音$ 3 \ Mathbf {q}单-$ \ Mathbf {q} $ rcdw订单,称为$ 2 \ Mathbf {q} $ - $ 1 \ Mathbf {q} $。此外,我们确定了七种不同类型的ICDW顺序,这是由于在费米水平上方和下方存在的两对范霍夫奇异性的不同钒骨和kagome-Sublattice结构所致。 While the $2\mathbf{Q}$-$1\mathbf{Q}$ states trigger an orthorhombic distortion that breaks the threefold rotational symmetry of the kagome lattice, the $3\mathbf{Q}$-$3\mathbf{Q}$ states induce various types of subsidiary uniform magnetic orders, from conventional ferromagnetism to magnetic八极极,磁环,甚至是磁性单极顺序。我们表明,这些外来的订单显示了独特的磁性曲线,磁电磁性和磁性电视曲目特性,可以实验探测以识别在这些化合物中实现了哪种ICDW状态。我们简要讨论了电荷顺序的平面外调制以及这些复杂的电荷订购状态与超导性之间的相互作用的影响。

Experiments in the recently discovered vanadium-based kagome metals have suggested that their charge-ordered state displays not only bond distortions, characteristic of a ``real" charge density-wave (rCDW), but also time-reversal symmetry-breaking, typical of loop currents described by an ``imaginary" charge density-wave (iCDW). Here, we combine density-functional theory, group-theory, and phenomenological modeling to investigate the complex charge-ordered states that arise from interactions between the low-energy van Hove singularities present in the electronic structure of $A$V$_3$Sb$_5$. We find two broad classes of mixed iCDW-rCDW configurations: triple-$\mathbf{Q}$ iCDW, triple-$\mathbf{Q}$ rCDW order, dubbed $3\mathbf{Q}$-$3\mathbf{Q}$, and double-$\mathbf{Q}$ iCDW, single-$\mathbf{Q}$ rCDW order, dubbed $2\mathbf{Q}$-$1\mathbf{Q}$. Moreover, we identify seven different types of iCDW order, stemming from the different vanadium-orbital and kagome-sublattice structures of the two pairs of van Hove singularities present above and below the Fermi level. While the $2\mathbf{Q}$-$1\mathbf{Q}$ states trigger an orthorhombic distortion that breaks the threefold rotational symmetry of the kagome lattice, the $3\mathbf{Q}$-$3\mathbf{Q}$ states induce various types of subsidiary uniform magnetic orders, from conventional ferromagnetism to magnetic octupolar, magnetic toroidal, and even magnetic monopolar order. We show that these exotic orders display unique magneto-striction, magneto-electric, and magneto-electric-striction properties that can be probed experimentally to identify which iCDW state is realized in these compounds. We briefly discuss the impact of an out-of-plane modulation of the charge order and the interplay between these complex charge-ordered states and superconductivity.

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