Ferromagnetic interlayer coupling in FeSe1−xSx superconductors revealed by inelastic neutron scattering

Journal article

FeSe1-xSx superconductors are commonly considered layered van der Waals materials with negligible interlayer coupling. Here, using inelastic neutron scattering to study spin excitations in single-crystal samples, we reveal that the magnetic coupling between adjacent Fe layers is ferromagnetic in nature, making the system different from most unconventional superconductors including iron pnictides. The weak interlayer coupling is estimated to be Jc∼ 0.2 meV, in agreement with the short spin-spin correlation length ζc∼0.2c along the c axis. The results provide an experimental basis for establishing a microscopic theoretical model to describe the absence of magnetic order in FeSe1-xSx.

Authors: Ma, M; Bourges, P; Sidis, Y; Sun, J; Wang, G

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Physical Society
• Journal: Physical Review B (condensed matter and materials physics)
• Volume: 110
• Issue: 17
• Article number: 174503
• Publication date: 2024-11-05
• Acceptance date: 2024-10-24
• DOI: 10.1103/physrevb.110.174503
• EISSN: 2469-9969
• ISSN: 2469-9950
• Language: English
• Keywords: superconducting fluctuations; pairing mechanisms; time-of-flight neutron spectroscopy; magnetic interactions; spin dynamics; FFR