Just published in Acta Materialia, using the detailed analysis of transmission electron microscopy (TEM) data, researchers from the LSME identify a novel growth mechanism of grain triplets in polycrystalline thin films of ZnO. The study primarily depends on the mining of data acquired using automated crystal orientation mapping with scanning nanobeam electron diffraction, which is complemented by high resolution TEM imaging and correlated to scanning electron microscopy of the film’s surface morphology. Remarkably, all three boundaries between the grains in each triplet correspond to low energy coherent twins, achieved by one of the grains rotating internally across its volume. It is hoped that the study will stimulate new research to simulated and understand the mechanisms behind this.