Category archives: Materials

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 […]

One of the unique features of the chemistry of carbon (and, to some extent, silicon) is its ability to form long chains of atoms. Polymers are substances that have macromolecules composed of many repeating units (known as ‘mers’). Many naturally occurring substances are polymers, including rubber and many substances based on glucose, such as the […]

Introducing a gaseous phase into a solid matrix is one of the most common strategies to reduce weight and increase thermal insulation in a wide range of materials, from ceramics to metals and polymers. How to produce these two-phase materials is mostly determined by the nature of the solid matrix and has led to the […]

Organic-based materials have gained rising interest as active components in electronics, energy conversion and catalytic systems. However, the discrete nature of the molecular constituents of these systems implies a reduced electron conductance, lowering the device efficiency. In order to increase the electron delocalization through an improved structural order, which favors orbital overlap and consequently the […]

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 dose makes the poison!” This adage, attributed to Paracelsus, explains a basic principle of toxicology: a substance can produce a harmful effect only if it reaches a certain “toxic” concentration.[1] In reverse, it also means that a substance is not harmful below this toxic dose, and can even be vitally important for a biological […]

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 […]