kvasikristallit

Kvasikristallit, also known as quasicrystals, are solid materials that exhibit atomic arrangements which are ordered but not periodic. Unlike conventional crystals, which have repeating patterns of atoms, quasicrystals possess a structure that is ordered in a non-repeating, or quasiperiodic, way. This means that while there is a definite arrangement and spacing of atoms, this pattern does not simply repeat itself indefinitely like a wallpaper pattern.

The discovery of quasicrystals in 1982 by Dan Shechtman was groundbreaking, challenging the long-held definition of a crystal as necessarily periodic. Shechtman observed a unique five-fold rotational symmetry in an alloy of aluminum and manganese, a symmetry that is impossible in periodic crystals. This observation led to the development of a new class of materials.

The atomic structure of quasicrystals can be described using mathematical concepts like Penrose tilings. These tilings use different shapes that fit together without overlapping and without forming a repeating pattern, yet they are ordered. Similarly, the atoms in a quasicrystal are arranged according to these quasiperiodic rules.

Quasicrystals possess a range of interesting properties, including low friction, high hardness, and excellent electrical insulation. These characteristics make them candidates for various applications, such as in coatings for cookware, aerospace components, and potentially in electronic devices. Despite their unique structure, they are considered a distinct phase of matter.