Nature of the spin resonance mode in CeCoIn5
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...
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Veröffentlicht in: | Communications physics 2020-05, Vol.3 (1), Article 98 |
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Sprache: | eng |
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Zusammenfassung: | 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.
Spin mediated unconventional superconductivity exhibits a sign changing order parameter which is often inferred from the observation of a spin resonance mode. Here, the authors demonstrate that the origin of the spin resonance mode for a heavy fermion superconductor may not lie, as previously thought, in the spin-excitonic bound state and therefore its relation to the ordering parameter needs to be reconsidered. |
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ISSN: | 2399-3650 2399-3650 |
DOI: | 10.1038/s42005-020-0365-8 |