Electronic Structure of ThPd$_2$Al$_3$: an impact of the U $5f$ states in the electronic structure of UPd$_2$Al$_3$

TL;DR

This study investigates the electronic structure of ThPd$_2$Al$_3$ using photoelectron spectroscopy and compares it with UPd$_2$Al$_3$, revealing the significant role of U 5f states in the latter's Fermi surface and three-dimensional electronic nature.

Contribution

The paper provides the first detailed comparison of the electronic structures of ThPd$_2$Al$_3$ and UPd$_2$Al$_3$, highlighting the impact of U 5f states on the Fermi surface topology.

Findings

ThPd$_2$Al$_3$'s Fermi surface mainly consists of Al 3p and Th 6d states.

U 5f states in UPd$_2$Al$_3$ hybridize with Al 3p states.

UPd$_2$Al$_3$ exhibits a strongly three-dimensional Fermi surface.

Abstract

The electronic structure of ThPd$_2$Al$_3$, which is isostructural to the heavy fermion superconductor UPd$_2$Al$_3$, was investigated by photoelectron spectroscopy. The band structure and Fermi surfaces of ThPd$_2$Al$_3$ were obtained by angle-resolved photoelectron spectroscopy (ARPES), and the results were well-explained by the band-structure calculation based on the local density approximation. The comparison between the ARPES spectra and the band-structure calculation suggests that the Fermi surface of ThPd$_2$Al$_3$ mainly consists of the Al $3p$ and Th $6d$ states with a minor contribution from the Pd $4d$ states. The comparison of the band structures between ThPd$_2$Al$_3$ and UPd$_2$Al$_3$ argues that the U $5f$ states form Fermi surfaces in UPd$_2$Al$_3$ through hybridization with the Al $3p$ state in the Al layer, suggesting that the Fermi surface of UPd$_2$Al$_3$ has a strong three-dimensional nature.