标题： 范德瓦尔斯磁体 Fe4GeTe2 中的动力学电子关联和手性磁性 显示英文标题

标题： Dynamical electronic correlation and chiral magnetism in van der Waals magnet Fe4GeTe2

摘要： 在准二维范德瓦尔斯磁性系统中，Fe4GeTe2因其接近室温的铁磁行为以及复杂的磁热相图表现出的多重相变而具有深远影响，这些相变通过磁化率和磁输运测量得以观察。 现有文献中尚未有针对这些相变在电子关联及其对底层磁相互作用影响方面的完整分析。 采用基于第一性原理的方法，结合电子关联的动态性质，我们分析了易面内和易轴方向上磁化方向与晶体对称性的相互作用，揭示了自旋重取向转变（SRT）温度以上伪能隙特征的打开。 与现有实验观测结果相比，动态关联对Fe原子L边磁圆二色性和X射线吸收谱的影响计算结果一致。 计算得到的Fe间海森堡交换相互作用表现出复杂特性，取决于两个不等价Fe位点之间的成对相互作用，表明磁相互作用具有RKKY类行为。 我们注意到显著的各向异性及反对称交换相互作用的存在，导致系统磁行为出现手性。 进一步研究Fe4GeTe2磁性的动力学方面及其相应的磁热相图显示，自旋的动力学特性和Fe两位置磁性属性的解耦对于解释所有实验观测到的相变至关重要。 显示英文摘要

摘要： Among the quasi-2D van der Waals magnetic systems, Fe4GeTe2 imprints a profound impact due to its near-room temperature ferromagnetic behaviour and the complex magnetothermal phase diagram exhibiting multiple phase transformations, as observed from magnetization and magnetotransport measurements. A complete analysis of these phase transformations in the light of electronic correlation and its impact on the underlying magnetic interactions remain unattended in the existing literature. Using first-principles methodologies, incorporating the dynamical nature of electron correlation, we have analysed the interplay of the direction of magnetization in the easy-plane and easy-axis manner with the underlying crystal symmetry, which reveals the opening of a pseudogap feature beyond the spin-reorientation transition (SRT) temperature. The impact of dynamical correlation on the calculated magnetic circular dichroism and x-ray absorption spectrum of the L-edge of the Fe atoms compared well with the existing experimental observations. The calculated intersite Heisenberg exchange interactions display a complicated nature, depending upon the pairwise interactions among the two inequivalent Fe sites, indicating a RKKY-like behaviour of the magnetic interactions. We noted the existence of significant anisotropic and antisymmetric exchanges interactions, resulting into a chirality in the magnetic behaviour of the system. Subsequent investigation of the dynamical aspects of magnetism in Fe4GeTe2 and the respective magnetothermal phase diagram reveal that the dynamical nature of spins and the decoupling of the magnetic properties for both sites of Fe is crucial to explain all the experimentally observed phase transformations.