Electronic and crystalline structures of zero band-gap PdLuBi thin films grown epitaxially on MgO(100)

TL;DR

This study reports the successful epitaxial growth and detailed structural and electronic characterization of PdLuBi thin films, a potential topological insulator, revealing their high quality and agreement with theoretical predictions.

Contribution

It presents the first high-quality epitaxial PdLuBi thin films grown on MgO(100) and provides comprehensive structural and electronic analysis.

Findings

High-quality epitaxial PdLuBi films confirmed by X-ray and RHEED

Films exhibit low surface roughness (~1.45 nm)

Valence band spectra match ab-initio calculations

Abstract

Thin films of the proposed topological insulator PdLuBi - a Heusler compound with the C1b structure - were prepared on Ta-Mo-buffered MgO(100) substrates by co-sputtering from PdBi2 and Lu targets. Epitaxial growth of high-quality PdLuBi films was confirmed by X-ray spectrometry and reflection high-energy electron diffraction. The root-mean-square roughness of the films was as low as 1.45 nm, although the films were deposited at high temperature. The film composition is close to the ideal stoichiometric ratio. The valence band spectra of the PdLuBi films, observed by hard X-ray photoelectron spectroscopy, correspond perfectly to the ab-initio-calculated density of states.