Study of the isotropic contribution to the analysis of photoelectron diffraction experiments at the ALOISA beamline

TL;DR

This paper develops an analytical model to quantify the isotropic contribution in photoelectron diffraction experiments, considering instrumental and sample properties, with application to Fe/Cu3Au(001) data at the ALOISA beamline.

Contribution

It introduces a detailed analytical treatment of instrumental effects on ISO components in photoelectron diffraction, tailored for the ALOISA beamline's experimental configurations.

Findings

Analytical formulas for instrumental ISO contributions are derived.

Application to Fe/Cu3Au(001) demonstrates model effectiveness.

Surface parameters like overlayer thickness and roughness are incorporated.

Abstract

The angular distribution of the intensity in photoemission experiments is affected by electron diffraction patterns and by a smoothly varying ISO contribution originated by both intrumental details and physical properties of the samples. The origin of the various contributions to the ISO component has been identified since many years. Nonetheless in this work we present original developement of the ED analysis, which arises from the evolution of instrumental performance, in terms of analyzers positioning and angular resolution, as well as collimation and size of X-ray beams in third generation synchrotron sources. The analytical treatement of the instrumental factors is presented in detail for the end station of the ALOISA beamline (Trieste Synchrotron), where a wide variety of scattering geometries is available for ED experiments. We present here the basic formulae and their application to experimental data taken on the Fe/Cu3Au(001) system in order to highlight the role of the various parameters included in the distribution function. A specific model for the surface illumination has been developed as well as the overlayer thickness and surface roughness have been considered.