Quasi-periodic Materials – Crystal Redefined

Crystallography has been one of the mature sciences. Over the years, the modern science of crystallography that started by experimenting with x-ray diffraction from crystals in 1912 has developed a major paradigm -that all crystals are ordered and periodic. Indeed, this was the basis for the definition of "crystal" in textbooks on crystallography and x-ray diffraction. Based upon a vast number of experimental data, constantly improving research tools, and deepening theoretical understanding of the structure of crystalline materials no revolution was anticipated in our understanding the atomic order of solids.