Won Kyung Seong

arising from S. Kim et al. Nature Communications (https://doi.org/10.1038/s41467-024-46502-6) (2024). We report scientific and technical queries regarding the article reported by Kim et al.1, (referred to as ref. 1 hereafter) on the mechanical properties of graphene-poly(methyl methacrylate) (PMMA) composites.

Abstract Graphite films with large grain sizes have been reportedly obtained by using metal as catalysts, but the obtained graphite is mostly heavily wrinkled, thus containing defects that degrade its properties. We report the synthesis of mirror-like and large-grained graphite films with only a few nano kinks and controllable dimensions, achieved by using flat Ni-Mo alloy melts of the same lateral dimensions as the metal foils used to make this alloy melt.

Abstract Natural diamonds were (and are) formed (thousands of million years ago) in the upper mantle of Earth in metallic melts at temperatures of 900–1,400 °C and at pressures of 5–6 GPa (refs. 1,2). Diamond is thermodynamically stable under high-pressure and high-temperature conditions as per the phase diagram of carbon3.