Spin dynamics in NaFeAs and NaFe0.53Cu0.47As probed by resonant inelastic x-ray scattering
Spin dynamics in NaFeAs and NaFe0.53Cu0.47As probed by resonant inelastic x-ray scattering
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DOI：
10.1103/physrevb.103.075112
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发表时间：
2021-01
影响因子：
3.7
通讯作者：
Yu Song;Weiyi Wang;E. Paris;Xingye Lu;J. Pelliciari;Y. Tseng;Yaobo Huang;D. McNally;M. Dantz;C. Cao;R. Yu;R. Birgeneau;T. Schmitt;P. Dai
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文献类型：
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作者：
Yu Song;Weiyi Wang;E. Paris;Xingye Lu;J. Pelliciari;Y. Tseng;Yaobo Huang;D. McNally;M. Dantz;C. Cao;R. Yu;R. Birgeneau;T. Schmitt;P. Dai
铁基超导体的母体化合物是磁有序的坏金属，超导性出现在假定的磁量子临界点附近。哈伯德排斥和洪德耦合的存在导致了这些多轨道系统中丰富的物理学，并激发了对巡游电子或局部自旋的磁性描述。NaFe 1 − x Cu x As系列由磁性有序的坏金属（x = 0）、超导（x ≥ 0）和非磁性金属（x = 0）组成。02)和磁有序的介导/绝缘（x ≤ 0 . 5)相，提供了一个平台，研究超导性，磁性和电子相关性之间的联系。在这里，我们使用x射线吸收光谱和共振非弹性x射线散射来研究两种NaFe 1 − x Cu x As化合物（x = 0和0.47）中Fe的价态和自旋动力学。我们发现这两种化合物的磁性都来自于Fe 2 +原子，并且在它们各自的有序态下都表现出欠阻尼色散自旋波。研究了NaFe 0 . 53 Cu 0 . [47] As与准一维一致。与NaFeAs相比，NaFe 0 . 53 Cu 0 . 47 As随着自旋激发的光谱权重显著增加而略微软化。我们的结果表明，自旋动力学在NaFe 0。53 Cu 0 . 47 As来自于局域磁矩，表明铁基超导体接近于具有局域铁磁矩的相关绝缘态。
The parent compounds of iron-based superconductors are magnetically ordered bad metals, with superconductivity appearing near a putative magnetic quantum critical point. The presence of both Hubbard repulsion and Hund’s coupling leads to rich physics in these multiorbital systems, and motivated descriptions of magnetism in terms of itinerant electrons or localized spins. The NaFe 1 − x Cu x As series consists of magnetically ordered bad metal ( x = 0), superconducting ( x ≈ 0 . 02) and magnetically ordered semiconducing / insulating ( x ≈ 0 . 5) phases, providing a platform to investigate the connection between superconductivity, magnetism and electronic correlations. Here we use x-ray absorption spectroscopy and resonant inelastic x-ray scattering to study the valence state of Fe and spin dynamics in two NaFe 1 − x Cu x As compounds ( x = 0 and 0.47). We find that magnetism in both compounds arises from Fe 2 + atoms, and exhibits underdamped dispersive spin waves in their respective ordered states. The dispersion of spin excitations in NaFe 0 . 53 Cu 0 . 47 As is consistent with being quasi-one-dimensional. Compared to NaFeAs, the band top of spin waves in NaFe 0 . 53 Cu 0 . 47 As is slightly softened with significantly more spectral weight of the spin excitations. Our results indicate the spin dynamics in NaFe 0 . 53 Cu 0 . 47 As arise from localized magnetic moments and suggest the iron-based superconductors are proximate to a correlated insulating state with localized iron moments.