2020/05/22 by Yu Song, Weiyi Wang, John S. Van Dyke +10 · 21 citations
Materials Science · Physics and Astronomy · #Bound state #Inelastic neutron scattering #Iron-based superconductors research #Mode (computer interface) #Momentum (technical analysis) #Rare-earth and actinide compounds #Resonance (particle physics) #Sign (mathematics) #Spin (aerodynamics) #Superconductivity #Superconductivity in MgB2 and Alloys #cond-mat.supr-con
paper · pdf · doi:10.1038/s42005-020-0365-8
published in Communications Physics 3(1) (Nature Portfolio) · accepted for publication in Communications Physics
openalex created_date 2020/05/21 · arxiv created 2020/05/22 · openalex publication_date 2020/05/29 · arxiv updated 2020/06/02 · openalex updated_date 2026/08/06
Abstract Spin-fluctuation-mediated unconventional superconductivity can emerge at the border of magnetism, featuring a superconducting order parameter that changes sign in momentum space. Detection of such a sign-change is experimentally challenging, since most probes are not phase-sensitive. The observation of a spin resonance mode (SRM) from inelastic neutron scattering is often seen as strong phase-sensitive evidence for a sign-changing superconducting order parameter, by assuming the SRM is a spin-excitonic bound state. Here we show that for the heavy fermion superconductor CeCoIn 5 , its SRM defies expectations for a spin-excitonic bound state, and is not a manifestation of sign-changing superconductivity. Instead, the SRM in CeCoIn 5 likely arises from a reduction of damping to a magnon-like mode in the superconducting state, due to its proximity to magnetic quantum criticality. Our findings emphasize the need for more stringent tests of whether SRMs are spin-excitonic, when using their presence to evidence sign-changing superconductivity.