Simultaneous probes of pseudogap and disorder by hard x-ray photoemission applied for a candidate thermoelectric Al-Pd-Ru quasicrystal

TL;DR

This study uses hard X-ray photoemission spectroscopy to investigate the electronic structure and disorder effects in Al-Pd-Ru quasicrystals, revealing a pseudogap near the Fermi level and site-specific contributions.

Contribution

It provides the first detailed analysis of the pseudogap and disorder effects in Al-Pd-Ru quasicrystals using HAXPES, highlighting site-specific electronic contributions.

Findings

Intrinsic pseudogap near the Fermi level observed

Al sites contribute significantly to the electronic structure

Disorder effects cause broadening of core-level lineshapes

Abstract

The bulk electronic structure of Al-Pd-Ru quasicrystal (QC) have been investigated by hard X-ray photoemission spectroscopy (HAXPES). We have found an intrinsic pseudogap structure in which the spectral weight in the vicinity of the Fermi level (E_F) is remarkably suppressed at any photon energy. The valence-band HAXPES spectra and the asymmetry of the core-level peaks indicate a contribution of the Al sites to the electronic structure in the vicinity of E_F with less contributions from the Pd and Ru sites. The disorder effects are found in the core-level lineshapes of the Al-Pd-Ru QC, of which the widths are much broader than those of the other reference crystalline solids with less disorder.