Lateral lattice coherence lengths in thin films of bismuth telluride topological insulators, with overview on polarization factors for X-ray dynamical diffraction in monochromator crystals

TL;DR

This paper develops a simple equation for determining lateral lattice coherence lengths in thin bismuth telluride films and reviews polarization effects in X-ray dynamical diffraction for monochromator crystals.

Contribution

It introduces a new simple equation for lateral lattice coherence length measurement and provides an overview of polarization factors in X-ray diffraction regimes.

Findings

Lateral lattice coherence length can be determined with a straightforward equation.

Polarization effects differ between kinematical and dynamical diffraction regimes.

The overview clarifies how polarization ratios are affected in monochromator crystals.

Abstract

In the supporting information file for article Dynamics of Defects in van der Waals Epitaxy of Bismuth Telluride Topological Insulators(J. Phys. Chem. C 2019, 123, 24818-24825, doi: 10.1021/acs.jpcc.9b05377), several topics on X-ray diffraction analysis of thin films were developed or revisited. A simple equation to determine lateral lattice coherence lengths in thin films stands as the main development (section S4 - Lateral lattice coherence length in thin films), while X-ray dynamical diffraction simulation in monochromator crystals stands as an interesting overview on how the ratio between $\pi$ and $\sigma$ polarization components is affected by whether diffraction takes place under kinematical or dynamical regime (section S3 - Polarization factor).