Angle-resolved X-ray photoemission electron microscopy

TL;DR

This paper reviews angle-resolved X-ray photoemission electron microscopy (XPEEM), demonstrating its capabilities for local electronic structure imaging, including a novel darkfield method achieving high-resolution mapping of electronic states in inhomogeneous materials.

Contribution

It introduces a darkfield XPEEM imaging technique for real space electronic structure mapping with high spatial resolution, expanding the application scope of angle-resolved PEEM.

Findings

Darkfield XPEEM achieves tens of nanometers resolution.

Technique is highly sensitive to local electronic structure variations.

Demonstrated on oxide surface with domain-specific electronic features.

Abstract

Synchrotron based photoemission electron microscopy with energy filter combines real space imaging with microprobe diffraction ($\mu$-ARPES), giving access to the local electronic structure of laterally inhomogeneous materials. We present here an overview of the capabilities of this technique, illustrating selected applications of angle resolved photoemission electron microscopy and related microprobe methods. In addition, we report the demonstration of a darkfield XPEEM (df-XPEEM) imaging method for real space mapping of the electronic structure away from $\Gamma$ at a lateral resolution of few tens of nm. The application of df-XPEEM to the (1$\times$12)-O/W(110) model oxide structure shows the high sensitivity of this technique to the local electronic structure, allowing to image domains with inequivalent adsorption site symmetry. Perspectives of angle resolved PEEM are discussed.