Category archives: Materials

Following the need for new and renewable sources of energy worldwide, fuel cells using electrocatalysts can be thought of as viable options. Catalyst materials modify and increase the rate of chemical reactions without itself undergoing any permanent change. An electrocatalyst is a catalyst that participates in electrochemical reactions and that functions at electrode surfaces or […]

When I first started writing about condensed matter science I found some difficulties with a few purely physical concepts, being myself a chemist by education. One of those was ‘polariton’. After some years of reading solid state physics papers and writing about them on a weekly basis, now is a familiar term, but I still […]

Mimicking natural processes has been a recurrent strategy for the development of new technologies, from velcro to bullet trains. Thanks to the advances in scientific knowledge and technological tools achieved over the last decades, biologically inspired research has evolved from the macroscale to the nanoscale. This poses an interdisciplinary challenge, involving fields such as molecular […]

For centuries, metals were employed in optical applications only as mirrors and gratings. New vistas opened up in the late 1970s and early 1980s with the discovery of surface-enhanced Raman scattering and the use of surface plasmon (collective electronic oscillations at the surface of metals) resonances for sensing. However, it was not until the 1990s […]

The scattering of conduction electrons in metals owing to impurities with magnetic moments is known as the Kondo effect, after Jun Kondo, who analysed the phenomenon in 1964. This scattering increases the electrical resistance and has the consequence that, in contrast to ordinary metals, the resistance reaches a minimum as the temperature is lowered and […]

A quantum dot is a nanometric crystalline structure of semiconductor materials. In a quatum dot electrons are confined in a region of space, thus creating a well defined structure of energy levels that depends very much on the size and shape of the quantum dot. This structure resembles that of atoms, that is why sometimes […]

The ability to trap and control particles with the help of well-controlled electromagnetic fields has led to revolutionary advances in the fields of biology, condensed- matter physics, high-precision spectroscopy, and quantum information, enabling unprecedented control both in the study of isolated single particles as well as in few and many-body systems subject to controlled and […]

A dielectric is a nonconductor of electric charge in which an applied electric field causes a displacement of charge but not a flow of charge. Light propagation through a dielectric medium is determined by the spatial distribution of the material. Photons scatter at local variations of the refractive index. Therefore, how ordered the medium is […]

When light encounters molecules, the predominant mode of scattering is elastic scattering (Rayleigh). This scattering is responsible for the blue colour of the sky, for example. It is also possible for the incident photons to interact with the molecules in such a way that energy is either gained or lost so that the scattered photons […]

Topological insulators are electronic materials that have a bulk band gap like an ordinary insulator but have conducting states on their edge or surface. The conducting surface is not what makes topological insulators unique, but the fact that it is protected due to the combination of spin-orbit interactions and time-reversal symmetry, the so-called topological surface […]