Quasicrystalleilla

Quasicrystals are a class of atomic structures that possess long-range order but lack translational periodicity. Unlike traditional crystals, which exhibit repeating patterns of atoms that can be described by a translation vector, quasicrystals have symmetries that are forbidden in conventional crystallography, such as five-fold rotational symmetry. This seemingly paradoxical nature arises from their unique atomic arrangements, which can be thought of as projections of higher-dimensional periodic structures.

The discovery of quasicrystals in 1982 by Dan Shechtman revolutionized the field of materials science. Prior to this, it was widely believed that materials with long-range order must also possess translational symmetry. Shechtman's observation of a diffraction pattern with icosahedral symmetry from an aluminum-manganese alloy challenged this fundamental assumption. His work was initially met with skepticism but eventually led to the Nobel Prize in Chemistry in 2011.

Quasicrystals exhibit a range of interesting properties. They are often hard, brittle, and possess low coefficients of friction, making them potentially useful in applications such as coatings and wear-resistant materials. Their unique electronic and thermal properties also suggest possibilities in fields like catalysis and thermoelectrics. Despite their unusual structure, quasicrystals are not defects but rather stable equilibrium phases in certain alloys. Research continues to explore new quasicrystalline materials and their potential technological applications.