Far-infrared probe of superconductivity in SmO$_{1-x}$F$_{x}$FeAs}

TL;DR

This study uses far-infrared reflectance measurements to investigate superconductivity in SmO$_{1-x}$F$_{x}$FeAs, revealing characteristic changes in reflectivity associated with the superconducting state.

Contribution

It provides the first detailed far-infrared optical analysis of SmO$_{1-x}$F$_{x}$FeAs superconductors, highlighting their reflectivity behavior and phonon interactions.

Findings

Superconductivity induces broad-range reflectivity changes.

Reflectivity ratio increases below 18 meV.

Presence of a strong infrared-active phonon at 10 meV.

Abstract

We report far-infrared reflectance measurements on polycrystalline superconducting samples of SmO$_{1-x}$F$_{x}$FeAs ($x$ = 0.12, 0.15 and 0.2). We clearly observe superconductivity induced changes of reflectivity in a broad range of energies, which resembles earlier optical measurements on high $T_{c}$ cuprates. The superconducting-to-normal reflectivity ratio $R_{s}/R_{n}$ grows for the photon energies below 18 meV and shows a complicated structure due to the presence of a strong infrared-active phonon at about 10 meV.