The atomic and electronic structures of NiO(001)∕Au(001) interfaces

Area of Science:

• Materials Science
• Surface Science
• Solid-State Physics

Background:

• Understanding metal oxide/metal interfaces is crucial for advanced electronic devices.
• Nickel oxide (NiO) and gold (Au) interfaces are relevant for catalysis and spintronics.

Purpose of the Study:

• To investigate the atomic and electronic structures of NiO(001)/Au(001) interfaces.
• To determine the impact of NiO film thickness on interface properties.

Main Methods:

• High-resolution medium energy ion scattering (MEIS) for atomic structure.
• Photoelectron spectroscopy (PES) and electron energy loss spectroscopy (EELS) for electronic structure.
• Synchrotron radiation light source for high-quality spectra.
• Density functional theory (DFT) calculations for theoretical validation.

Main Results:

• MEIS confirmed O atoms positioned above Au atoms with an inter-planar distance of 2.30 ± 0.05 Å.
• Metallic features were observed in valence band spectra for NiO thickness up to 3 monolayers (ML).
• Bandgap reduction in NiO films (5-10 ML) and significant electronic charge transfer from Au to NiO were detected.
• DFT calculations indicated an image charge beneath Ni atoms, explaining core level shifts.

Conclusions:

• The study elucidates the atomic arrangement and electronic behavior at NiO/Au interfaces.
• Thin NiO films exhibit metallic characteristics and reduced bandgaps, influenced by charge transfer and interface effects.
• The findings provide insights into interface phenomena relevant for nanoscale electronic applications.