December 2023

Symbolic picture for the article. The link opens the image in a large view.

Just in time for Advent, the stars arrange themselves in a highly symmetrical pattern.
The beautiful picture was actually created using electron diffraction, with the electron beam transmitting through a thin PbS film grown epitaxially on a TiS2 substrate. While the six-fold symmetry of the substrate is directly revealed by the strong reflections, the four-fold symmetry of the film remains hidden. The reason for this is that the PbS film grows in three orientation variants on the TiS2 in line with the six-fold symmetry of the whole pattern. Finally, each diffraction spot has its own origin.
It’s like Christmas: There is hidden magic but in the end every detail has its meaning.