Category archives: Condensed matter

Topological materials have special universal properties, which are protected against perturbations. Such properties are theoretically described by topology, a branch of mathematics concerned with the properties of geometrical objects that are unchanged by continuous deformations. Topological materials behave like an ordinary insulator in the bulk but have conducting states on their boundaries, i.e., edges or […]

A nanoantenna with balanced electric and magnetic dipole moments exhibits a directive radiation pattern with zero backscattering. This is known as the first Kerker condition after Kerker, Wang, and Giles, who predicted in 1983 that, under plane wave illumination, magnetic spheres with equal relative permittivity and permeability radiate no light in the backscattering direction. They […]

The most famous conjecture in condensed-matter physics was proposed in 1935, when Hillard Huntington and Eugene Wigner calculated the properties of hydrogen squeezed to high density and pressure. They predicted that under pressures above 25 gigapascals (GPa), hydrogen would undergo a density-driven transition from an insulating, molecular solid to a conducting, atomic solid. In their […]

The discovery of superconductivity in 2D films dates back over 80 years. Initially, these were 2D metallic films deposited on inert substrates, but in recent times more exotic 2D systems have exhibited superconducting properties, such as the surface of topological insulators or twisted bilayer graphene. Superconductivity is caused by the interactions between atomic vibrations (phonons) […]

An electric current can be visualized as a flow of electrons through a conducting piece of material. The less the resistance the material structure opposes to the flow of electrons the better a conductor it is. Part of this resistance appears at the surface, where electrons first encounter the material; as with electromagnetic radiation – […]

Future information and communication technologies will rely on the manipulation of not only electrons but also of light at the nanometer-scale. Squeezing light to such a small size has been a major goal in nanophotonics for many years. Particularly strong light squeezing can be achieved with polaritons, quasiparticles resulting from the strong coupling of photons […]

The magnitude of many of the exotic phenomena predicted for topological semimetals is directly proportional to something called the Chern number. Given the importance of the Chern number magnitude for these phenomena, it is just natural to wonder whether there is an upper limit for it and whether there are real materials in which this […]

No matter what you build or how much care you take building it, it would have defects. It seems it is a rule of nature: every time chaos gives way to order, from matter itself coming into existance in the very early universe to the formation of a crystal in a modern laboratory, defects appear […]

The concept of vector should be familiar: a quantity for which both magnitude and direction must be stated. This compares with a scalar quantity, where direction is not applicable, like temperature in a precise point. But, what if the magnitude varies with the direction? A vector would be a particular case, with only one direction […]

The Nobel Prize in Chemistry 2016 was awarded to Jean-Pierre Sauvage, Fraser Stoddart and Ben Feringa “for the design and synthesis of molecular machines”. Molecular machines are made by one or a few molecules linked together, comprising several hundred atoms. If a molecule can use an energy input to perform a mechanical movement (output) it […]