Preferred spin excitations in the bilayer iron-based superconductor CaKðFe0.96Ni0.04Þ4As4 with spin-vortex crystal order
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Date
2022-03-31
Journal Title
Journal ISSN
Volume Title
Publisher
American Physical Society
Abstract
Spin-orbit coupling (SOC) is a key to understand the magnetically driven superconductivity in iron-based superconductors, where both local and itinerant electrons are present and the orbital angular momentum is not completely quenched. Here, we report a neutron scattering study on the bilayer compound CaK(Fe0.96Ni0.04)4As4 with superconductivity coexisting with a noncollinear spin-vortex crystal magnetic order that preserves the tetragonal symmetry of the Fe-Fe plane. In the superconducting state, two spin resonance modes with odd and even L symmetries due to the bilayer coupling are found similar to the undoped compound CaKFe4As4 but at lower energies. Polarization analysis reveals that the odd mode is c-axis polarized, and the low-energy spin anisotropy can persist to the paramagnetic phase at high temperature, which closely resembles other systems with in-plane collinear and c-axis biaxial magnetic orders. These results provide the missing piece of the puzzle on the SOC effect in iron-pnictide superconductors, and also establish a common picture of c-axis preferred magnetic excitations below Tc regardless of the details of magnetic pattern or lattice symmetry. © 2022 American Physical Society
Description
Attached copy comes from https://arxiv.org/abs/2202.11933 which is CC-BY licence.
Keywords
Spin, Excitation, Superconductors, Crystals, Iron, Symmetry, Electrons, Scattering, Polarization, Temperature range 0400-1000 K
Citation
Liu, C., Bourges, P., Sidis, Y., Xie, T., He, G., Bourdarot, F., Danilkin, S., Ghosh, H., Ghosh, S., Ma, X., Li, S., Li, Y., & Luo, H. (2022). Preferred spin excitations in the bilayer iron-based superconductor CaKðFe0.96Ni0.04Þ4As4 with spin-vortex crystal order. Physical Review Letters, 128(13), 137003. doi:10.1103/PhysRevLett.128.137003