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Schematic of aperiodic structures. (a) Crystal with incommensurate displacive modulation, in which atom positions deviate periodically from those of a conventional periodic crystal. (b) 2D model of an incommensurate composite. (c) 2D Penrose tiling quasicrystal constructed by a skinny rhombus with an angle of 36° and a fat rhombus with an angle of 72°. The schemes are based on those in ref. [17].
