Quasiperiodic structures, or quasicrystals, because of their unique ordering of atoms and a lack of periodicity, possess remarkable crystallographic, physical and optical properties not present in regular crystals.
Figure Caption: Two-dimensional Penrose type quasicrystal made using only two tile shapes: a thick rhomb and a thin rhomb. The structure proposed by Roger Penrose lacks translational symmetry and exhibits five-fold rotational symmetry not allowed in regular crystals.
Periodic structures are known for their predictable symmetry, both rotational and translational, and they were believed to be the only kinds of repeating structures that could occur in nature. From basic solid state physics, these structures are only allowed to exhibit strict 2, 3, 4 or 6-fold rotational symmetry, i.e., upon rotation by a certain angle about a crystallographic axis, the shape would still look identical upon each rotation. It was not believed that there could be a structure that existed which violated these four symmetry rules. Random systems, the other big area of research, looks at amorphous or disordered media like gases.
The introduction of quasicrystals – an ordered structure that lacks periodicity, exhibits some properties similar to periodic structures (such as atomic ordering over large-length scales) while violates rotational symmetry rules associated with them (i.e., a quasicrystal can exhibit 5 or 8 fold rotational symmetry) – was an area initially met with resistance from the research community. Agrawal explores this transition from skepticism to the ultimate acceptance by a growing number of researchers exploring the potential of these unique structures.
Ariel DuChene | EurekAlert!
Bergamotene - alluring and lethal for Manduca sexta
21.04.2017 | Max-Planck-Institut für chemische Ökologie
How to color a lizard: From biology to mathematics
13.04.2017 | Université de Genève
Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.
For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...
What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.
To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...
The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....
A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...
Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision
Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...
21.07.2017 | Event News
19.07.2017 | Event News
12.07.2017 | Event News
21.07.2017 | Earth Sciences
21.07.2017 | Power and Electrical Engineering
21.07.2017 | Physics and Astronomy