One of the most common observations in point-contact spectra on the recently discovered ferropnictide superconductors is a large conductance asymmetry with respect to voltage across the point-contact. In this paper, we show that the antisymmetric part of the point-contact spectrum between a silver tip and an epitaxial thin film of Ba (Fe0.92 Co0.08)2 As2 shows certain unique features that have an interesting evolution with increasing temperature up to a temperature far above the critical temperature Tc. We associate this observation with the existence of a gap above Tc that might originate from strong fluctuations of the phase of the superconducting order parameter.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)