Absence of a Large Superconductivity-Induced Gap in Magnetic Fluctuations of Sr_{2}RuO_{4}

Phys Rev Lett. 2017 Apr 7;118(14):147002. doi: 10.1103/PhysRevLett.118.147002. Epub 2017 Apr 5.

Abstract

Inelastic neutron scattering experiments on Sr_{2}RuO_{4} determine the spectral weight of the nesting induced magnetic fluctuations across the superconducting transition. There is no observable change at the superconducting transition down to an energy of ∼0.35 meV, which is well below the 2Δ values reported in several tunneling experiments. At this and higher energies magnetic fluctuations clearly persist in the superconducting state. Only at energies below ∼0.3 meV can evidence for partial suppression of spectral weight in the superconducting state be observed. This strongly suggests that the one-dimensional bands with the associated nesting fluctuations do not form the active, highly gapped bands in the superconducting pairing in Sr_{2}RuO_{4}.