Investigation of Superconducting Gap Structure in TbFeAsO$_{0.9}$F$_{0.1}$ using Point Contact Andreev Reflection

TL;DR

This study uses point contact Andreev reflection spectroscopy to investigate the superconducting gap structure in TbFeAsO$_{0.9}$F$_{0.1}$, revealing multiple gaps and potential nodal features.

Contribution

It provides the first detailed spectroscopic analysis of the gap structure in TbFeAsO$_{0.9}$F$_{0.1}$, identifying multiple gap-like features and discussing their implications.

Findings

Evidence for multiple superconducting gaps.

Observation of high bias shoulders in spectra.

Potential indication of nodal superconductivity.

Abstract

Bulk samples of TbFeAsO$_{0.9}$F$_{0.1}$ (T$_{c}$(on) = 50K) were measured by point contact Andreev reflection spectroscopy. The spectra show unambiguous evidence for multiple gap-like features plus the presence of high bias shoulders. By measuring the spectra as a function of temperature with both gold and superconducting niobium tips, we establish that the gap-like features are associated with superconducting order parameter in this material. We discuss whether the well defined zero bias conductance peak that we observe infrequently is associated with a nodal superconducting order parameter.