Magnetic interactions and possible structural distortion in kagome FeGe from first-principles calculations and symmetry analysis
Magnetic interactions and possible structural distortion in kagome FeGe from first-principles calculations and symmetry analysis
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DOI：
10.1103/physrevb.108.035138
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发表时间：
2022-11
影响因子：
3.7
通讯作者：
Han Zhou;S. Yan;Dongze Fan;Di Wang;X. Wan
中科院分区：
文献类型：
--
作者：
Han Zhou;S. Yan;Dongze Fan;Di Wang;X. Wan
基于密度泛函理论和对称性分析，对磁性金属铁锗的电子结构、磁性能和可能的结构畸变进行了全面的研究。我们估计了包括Heisenberg和Dzyaloshinskii-Moriya （DM）相互作用在内的磁性参数，发现最近邻的铁磁性$J_{1}$占主导地位，而最近的kagome层之间的磁性相互作用倾向于反铁磁性。成功地再现了N\ {e}el温度$T_{N}$和居里-魏斯温度$\theta _{CW}$，计算得到的磁各向异性能也与实验结果一致。然而，这些合理的海森堡相互作用和磁各向异性并不能解释双锥磁转变，而DM相互作用甚至存在于中心对称材料中，也会导致这种小的磁锥角。不幸的是，由于高温结构的晶体对称性，DM相互作用对双锥磁结构的净贡献是不存在的。基于实验的$2\ × 2\ × 2$超级单体，我们由此探索了母相的子群。群理论分析表明，存在68种不同的扭曲，其中只有4种（空间群$P622$或$P6_{3}22$）没有反转和镜像对称，因此可以解释低温磁结构。此外，我们认为这四种CDW相可以用拉曼光谱来识别。由于DM相互作用对小原子位移和对称限制非常敏感，我们认为对称分析是揭示微妙结构畸变和复杂磁构型相互作用的有效方法。
Based on density functional theory and symmetry analysis, we present a comprehensive investigation of electronic structure, magnetic properties and possible structural distortion of magnetic kagome metal FeGe. We estimate the magnetic parameters including Heisenberg and Dzyaloshinskii-Moriya (DM) interactions, and find that the ferromagnetic nearest-neighbor $J_{1}$ dominates over the others, while the magnetic interactions between nearest kagome layers favors antiferromagnetic. The N\'{e}el temperature $T_{N}$ and Curie-Weiss temperature $\theta _{CW}$ are successfully reproduced, and the calculated magnetic anisotropy energy is also in consistent with the experiment. However, these reasonable Heisenberg interactions and magnetic anisotropy cannot explain the double cone magnetic transition, and the DM interactions, which even exist in the centrosymmetric materials, can result in this small magnetic cone angle. Unfortunately, due to the crystal symmetry of the high-temperature structure, the net contribution of DM interactions to double cone magnetic structure is absent. Based on the experimental $2\times 2\times 2$ supercell, we thus explore the subgroups of the parent phase. Group theoretical analysis reveals that there are 68 different distortions, and only four of them (space group $P622$ or $P6_{3}22$) without inversion and mirror symmetry thus can explain the low-temperature magnetic structure. Furthermore, we suggest that these four proposed CDW phases can be identified by using Raman spectroscopy. Since DM interactions are very sensitive to small atomic displacements and symmetry restrictions, we believe that symmetry analysis is an effective method to reveal the interplay of delicate structural distortions and complex magnetic configurations.