According to how the electronic band theory is usually explained, solids can be classified as insulators, semiconductors, or metals. But, actually, there is another kind of solid between semiconductors and metals, the semimetals. In insulators and semiconductors the filled valence band is separated from an empty conduction band by a band gap, in metals there […]
In 1882, Heinrich Hertz devoted himself to the study of electromagnetism, including the recent and still generally unappreciated work of Maxwell. Two years later he began his famous series of experiments with electromagnetic waves. During the course of this work, Hertz discovered the photoelectric effect, which has had a profound influence on modern physics. The […]
Major technological revolutions have occurred when the humankind has been able to harness natural resources, such as fire, electricity or nuclear energy. We are now in the verge of the so called second quantum revolution, that aims to harness two of the weirdest natural resources, coherence and entanglement. This is a tall order that calls […]
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. Researchers are chasing efficient […]
Since the discovery that graphene, the two dimensional carbon allotrope, can be isolated and incorporated into electronic devices intense research efforts have been triggered. Driving forces behind the experimental and theoretical studies of graphene are, e.g., the exceptional electronic properties, in particular the high electron mobilities, the long spin coherence lengths and the possibility to […]
We know that incident light can provoke a strong optical response in metallic nanostructures due to the excitation of resonant plasmonic modes, i.e, the electrons in the metal become excited by the photons in the incident light and oscillate collectively. Plasmonic nanoparticles can significantly modify the optical properties of nearby organic molecules and thus present […]
Condensed matter • Materials • Nanotechnology • Quantum physics
The Pioneer plaques are a pair of gold–anodized aluminium plaques which were placed on board the 1972 Pioneer 10 and 1973 Pioneer 11 spacecraft, featuring a pictorial message, in case either Pioneer 10 or 11 is intercepted by extraterrestrial life. The plaques show the nude figures of a human male and female along with several […]
Graphene is one of the most promising materials for nanoelectronics owing to its unique Dirac cone-like dispersion of the electronic state and high mobility of the charge carriers. We all know that already, provided we are a little bit interested in condensed matter physics. But the point is that, in order to facilitate the implementation […]
Graphene nanoribbons (GNRs), are strips of graphene with ultra-thin width (<50 nm). Graphene ribbons were introduced as a theoretical model by Mitsutaka Fujita and coauthors to examine the edge and nanoscale size effect in graphene. GNRs are very interesting structures, partly due to their attractive electronic properties. Those properties vary dramatically with changes in the […]
During World War II the Germans relied on their strong chemical knowledge to overcome the limited access to critical raw materials that the circumstances of the war itself imposed. One of these raw materials was Chilean saltpeter (sodium nitrate), which was the base for explosives. The solution was to use a chemical process designed to […]