Electronic Structure of UTe$_2$ Studied by Photoelectron Spectroscopy

TL;DR

This study investigates the electronic structure of the unconventional superconductor UTe$_2$ using advanced photoelectron spectroscopy techniques, revealing itinerant yet strongly correlated U 5f states with hybridization effects.

Contribution

The paper provides detailed experimental insights into the U 5f electronic states and their hybridization in UTe$_2$, highlighting effects not captured by standard band structure calculations.

Findings

U 5f states are itinerant with strong electron correlation effects.

Anomalous U 5f and Te 5p state admixture observed at high binding energies.

Overall band structure largely agrees with calculations.

Abstract

The electronic structure of the unconventional superconductor UTe$_2$ was studied by resonant photoelectron spectroscopy (RPES) and angle-resolved photoelectron spectroscopy (ARPES) with soft X-ray synchrotron radiation. The partial $\mathrm{U}~5f$ density of states of UTe$_2$ were imaged by the $\mathrm{U}~4d$--$5f$ RPES and it was found that the $\mathrm{U}~5f$ state has an itinerant character, but there exists an incoherent peak due to the strong electron correlation effects. Furthermore, an anomalous admixture of the $\mathrm{U}~5f$ states into the $\mathrm{Te}~5p$ bands was observed at a higher binding energy, which cannot be explained by band structure calculations. On the other hand, the band structure of UTe$_2$ was obtained by ARPES and its overall band structure were mostly explained by band structure calculations. These results suggest that the $\mathrm{U}~5f$ states of UTe$_2$ have itinerant but strongly-correlated nature with enhanced hybridization with the $\mathrm{Te}~5p$ states.