Electronic structure of URu$_2$Si$_2$ in paramagnetic phase: Three-dimensional angle resolved photoelectron spectroscopy study

TL;DR

This study uses 3D angle-resolved photoelectron spectroscopy to map the electronic structure of URu$_2$Si$_2$ in its paramagnetic phase, revealing 3D quasi-particle bands with strong correlations crucial for understanding its hidden order.

Contribution

First comprehensive 3D electronic structure mapping of URu$_2$Si$_2$ in the paramagnetic phase using ARPES, highlighting the 3D nature and strong correlations of quasi-particle bands.

Findings

Quasi-particle bands with U 5f contribution near E_F were observed.

The band dispersion varies significantly with k_z, indicating a 3D electronic structure.

Band-structure calculations qualitatively match experimental features despite strong correlations.

Abstract

The three-dimensional (3D) electronic structure of the hidden order compound URu$_2$Si$_2$ in a paramagnetic phase was revealed using a 3D angle-resolved photoelectron spectroscopy where the electronic structure of the entire Brillouin zone is obtained by scanning both incident photon energy and detection angles of photoelectrons. The quasi-particle bands with enhanced contribution from the $\mathrm{U}~5f$ state were observed near $E_\mathrm{F}$, formed by the hybridization with the $\mathrm{Ru}~4d$ states. The energy dispersion of the quasi-particle band is significantly depend on $k_z$, indicating that they inherently have a 3D nature. The band-structure calculation qualitatively explain the characteristic features of the band structure and Fermi surface although the electron correlation effect strongly renormalizes the quasi-particle bands. The 3D and strongly-correlated nature of the quasi-particle bands in URu$_2$Si$_2$ is an essential ingredient for modeling its hidden-order transition.