Unveiling the 5$f$ electron hybridization process in UPd$_2$Al$_3$ via ARPES and Time-resolved PES

TL;DR

This paper uses ARPES and time-resolved PES to study 5f-electron hybridization in UPd2Al3, revealing a hybridization gap formation, persistent flat bands, and complex temperature-dependent electronic interactions relevant to heavy fermion superconductivity.

Contribution

It provides detailed experimental insights into the temperature evolution of 5f-electron hybridization in UPd2Al3, highlighting unconventional behaviors and their implications for heavy fermion physics.

Findings

Hybridization gap forms around 75 K

Persistent flat U 5f band above hybridization temperature

Non-monotonic quasiparticle relaxation time with an anomaly at 20 K

Abstract

This study investigates the 5$f$-electron-conduction electron hybridization process in the heavy fermion superconductor UPd$_2$Al$_3$ using a combination of angle-resolved photoemission spectroscopy (ARPES) and time-resolved photoemission spectroscopy (tr-PES). ARPES measurements reveal the formation of a hybridization gap at a temperature of approximately 75 K, which becomes more pronounced as the temperature decreases. Notably, the persistence of a flat U 5$f$ band at temperatures well above the hybridization onset challenges conventional understanding. Our findings demonstrate a non-monotonic temperature dependence of the quasiparticle relaxation time, with an anomalous decrease at 20 K, suggesting complex electronic and magnetic interactions. These findings provide detailed insights into the 5$f$-electron hybridization process in UPd$_2$Al$_3$, with significant implications for the understanding of heavy fermion superconductivity and the role of 5$f$-electron hybridization in uranium-based materials.