Direct observation of quasi-particle band in CeIrIn$_5$: Angle-resolved photoemission spectroscopy study

TL;DR

This study uses high-resolution angle-resolved photoemission spectroscopy to observe a quasi-particle band in CeIrIn$_5$, revealing a small itinerant component in the 4$f$ electrons that contributes to its superconductivity.

Contribution

First direct observation of a quasi-particle band in CeIrIn$_5$ using ARPES, highlighting the itinerant nature of 4$f$ electrons in this heavy fermion superconductor.

Findings

Detected a ~30 meV dispersive quasi-particle band

Indicated a small itinerant component in 4$f$ electrons

Suggested the itinerant part contributes to superconductivity

Abstract

We have performed a high-resolution angle resolved Ce 4$d-4f$ resonant photoemission experiment on the heavy fermion superconductor CeIrIn$_5$. We have observed a quasi-particle band which has an energy dispersion of $\sim 30$ meV in the Ce 4$f$ on-resonance spectra. The result suggests that although the 4$f$ spectra are dominated by the localized/correlated character, the small itinerant component is responsible for the superconductivity in this compound.