Introduction

What is RHEED?

Reflection High Energy Electron Diffraction (RHEED) is an experimental technique widely used in surface science and thin film growth.

In RHEED, a beam of high-energy electrons (typically ~20-30 keV) strikes the sample surface at a grazing incidence angle (< 5°). Due to this geometry:

• The electrons interact only with the topmost atomic layers, making RHEED extremely surface-sensitive.

• The resulting diffraction pattern provides real-time feedback about the crystal structure, surface quality, and growth dynamics of thin films.

RHEED is especially useful during Molecular Beam Epitaxy (MBE), where it allows monitoring of surface reconstructions, layer-by-layer growth, and lattice parameters.

Project Goals

xRHEED is a flexible and extensible Python toolkit for analyzing RHEED data. It is designed as an xarray accessory library, meaning it integrates naturally with the scientific Python ecosystem.

Main features include:

• Load and preprocess RHEED images

• Generate and analyze intensity profiles

• Overlay predicted diffraction spot positions (kinematic theory & Ewald construction)

• Transform images into reciprocal (kx-ky) space

• Search for reconstruction lattice constants and rotations by calculating matching coefficients between experiment and theory

Note

xRHEED is not a GUI application. It is intended for use in interactive environments such as Jupyter notebooks, where flexibility and scriptability are essential.