Rheedium Theory and Architecture Guides¶
This documentation provides comprehensive coverage of the physics and software architecture underlying rheedium, a JAX-based framework for simulating Reflection High-Energy Electron Diffraction (RHEED) patterns.
Target Audience¶
These guides are written for physics researchers working with RHEED who want to understand:
The mathematical foundations of kinematic diffraction theory
How crystallographic data flows through the simulation pipeline
The physical meaning of simulation parameters and outputs
Guide Overview¶
Physics Foundations¶
Guide |
Description |
|---|---|
Complete walkthrough: From Ewald sphere to CTR rods for Si(111) |
|
Single-scattering approximation, structure factors, and intensity calculations |
|
Geometric diffraction conditions in reciprocal space |
|
Atomic scattering amplitudes and thermal (Debye-Waller) effects |
|
Crystal truncation rods, roughness damping, and finite domain effects |
|
Controlling which atomic layers contribute to RHEED patterns |
|
Simulating RHEED from any azimuth or surface orientation |
Data and Architecture¶
Guide |
Description |
|---|---|
Parsing XYZ, CIF, and POSCAR files; coordinate transformations |
|
Lattice vector construction, reciprocal space, and surface slabs |
|
JAX data structures enabling GPU acceleration and autodiff |
Quick Start¶
For hands-on examples, see the tutorials which demonstrate:
MgO kinematic simulation - Basic RHEED pattern generation
SrTiO3 simulation - Perovskite surface diffraction
Finite domain effects - Beam broadening and coherence
Mathematical Notation¶
Throughout these guides, we use:
\(\mathbf{k}\) for wavevectors (in \(\text{Å}^{-1}\))
\(\mathbf{G}\) for reciprocal lattice vectors
\(\mathbf{r}\) for atomic positions (in Å)
\((h, k, l)\) for Miller indices
\(\theta\) for grazing incidence angle
\(\phi\) for azimuthal angle
Equations are rendered using LaTeX notation compatible with GitHub and MathJax.