Changes in graphene interlayer distance induced by intercalation and quasicrystallization: a TRHEPD study

The physical properties of graphene can be dramatically altered by its interaction with the underlying substrate. The distance between the graphene layer and the substrate surface is a key parameter that governs these properties and serves as a sensitive indicator of the strength of interlayer coupling. In this review, we provide a comprehensive overview of recent results on the variation of interlayer distance obtained with total-reflection high-energy positron diffraction (TRHEPD), a technique that is exceptionally sensitive to the outermost atomic layers, focusing on three representative systems: (i) single-layer graphene grown on metal surfaces, (ii) foreign atom intercalation at the graphene-substrate interface, and (iii) graphene quasicrystals. These studies demonstrate how TRHEPD can resolve the changes in the graphene-substrate distance, thereby offering valuable insight into the mechanisms by which intercalation and quasicrystallization modify the electronic and thermal behavior of graphene.