X-ray diffraction data and analysis to support phase identification in FeSe and FeSe epitaxial thin films.

X-ray diffraction (XRD) data and analysis for epitaxial iron selenide thin films grown by pulsed laser deposition (PLD) are presented to support the conclusions in the related research article "Double epitaxy of tetragonal and hexagonal phases in the FeSe system" [1]. The films contain β-FeSe and FeSe phases in a double epitaxy configuration with the β-FeSe phase (001) oriented on the (001) MgO growth substrate. FeSe simultaneously takes on two different epitaxial orientations in certain growth conditions, exhibiting both (101)- and (001)- orientations. Each of these orientations are verified with the presented XRD data. Additionally, XRD data used to determine the PLD target composition as well as mosaic structure of the β-FeSe phase are shown.