Electronic Structures of CeM2Al10 (M = Fe, Ru, and Os) Studied by Soft X-ray Resonant and High-Resolution Photoemission Spectroscopies

TL;DR

This study investigates the electronic structures of CeM2Al10 compounds (M = Fe, Ru, Os) using soft X-ray resonant and high-resolution photoemission spectroscopies, revealing details about hybridization and magnetic ordering.

Contribution

It provides direct spectroscopic evidence of c-f hybridization and magnetic order in CeM2Al10, highlighting differences among M = Fe, Ru, Os, and identifying specific electronic structures related to these phenomena.

Findings

c-f hybridization strength varies (Ru < Os < Fe)

Pseudogap of 20-30 meV around Fermi level observed

Antiferromagnetic ordering associated with a shoulder at 10-11 meV

Abstract

We have performed a photoemission spectroscopy (PES) study of CeM2Al10 (M = Fe, Ru, and Os) to directly observe the electronic structure involved in the unusual magnetic ordering. Soft X-ray resonant (SXR) PES provides spectroscopic evidence of the hybridization between conduction and Ce 4f electrons (c-f hybridization) and the order of the hybridization strength (Ru < Os < Fe). High-resolution (HR) PES of CeRu2Al10 and CeOs2Al10, as compared with that of CeFe2Al10, identifies two structures that can be ascribed to structures induced by the c-f hybridization and the antiferromagnetic ordering, respectively. Although the c-f hybridization-induced structure is a depletion of the spectral intensity (pseudogap) around the Fermi level (EF) with an energy scale of 20-30 meV, the structure related to the antiferromagnetic ordering is observed as a shoulder at approximately 10-11 meV within the pseudogap. The energies of the shoulder structures of CeRu2Al10 and CeOs2Al10 are approximately half of the optical gap (20 meV), indicating that EF is located at the midpoint of the gap.