Extended Data Fig. 2: Characteristics of the CaF2 thin-film crystal surface.
From: Observation of the radiative decay of the 229Th nuclear clock isomer
An atomic force microscopy (AFM) image of the surface of the CaF2 thin film (a) and a reflection high-energy electron diffraction (RHEED) pattern along [11-2] azimuthal direction (b) are shown.