Iron Isotope Effect in SmFeAsO0.65 and SmFeAsO0.77H0.12 Superconductors: A Raman Study

TL;DR

This study investigates the iron isotope effect in SmFeAsO-based superconductors using Raman spectroscopy, revealing significant shifts in phonon modes that suggest a key role for electron-phonon coupling in their superconductivity.

Contribution

It provides the first detailed Raman analysis of isotope effects in SmFeAsO superconductors, highlighting the importance of electron-phonon interactions.

Findings

Significant phonon frequency shifts observed with different iron isotopes.

The isotope effect varies with isotopic substitution percentage.

Results suggest electron-phonon coupling is crucial in pairing mechanism.

Abstract

We report the inelastic light scattering studies on SmFeAsO0.65 and SmFeAsO0.77H0.12 with iron isotopes namely 54Fe and 57Fe. In both of these systems under investigation we observed a significant shift in the frequency of the phonon modes associated with the displacement of Fe atoms around ~ 200 cm-1. The observed shift in the Fe mode (B1g) for SmFeAsO0.65 is ~ 1.4 % and lower in case of SmFeAsO0.77H0.12, which is ~ 0.65 %, attributed to the lower percentage of isotopic substitution in case of SmFeAsO0.77H0.12. Our study reveals the significant iron isotope effect in these systems hinting towards the crucial role of electron-phonon coupling in the pairing mechanism of iron based superconductors.