Local quasiparticle density of states of superconducting SmFeAsO1-xFx single crystals: Evidence for spin-mediated pairing
Abstract
We probe the local quasiparticles density-of-states in micron-sized SmFeAsO1-xFx single-crystals by means of Scanning Tunnelling Spectroscopy. Spectral features resemble those of cuprates, particularly a dip-hump-like structure developed at energies larger than the gap that can be ascribed to the coupling of quasiparticles to a collective mode, quite likely a resonant spin mode. The energy of the collective mode revealed in our study decreases when the pairing strength increases. Our findings support spin-fluctuation-mediated pairing in pnictides.
0