Usually, the concept of exciton is linked to that of nonmetallic crystal: an electron-hole pair in a crystal that is bound in a manner analogous to the electron and proton of a hydrogen atom. It behaves like an atomic excitation (hence the name) that passes from atom to another and may be long-lived. Exciton behaviour […]
We are all familiar with the equation of ideal gases: PV = nRT. To deduce this equation, an ideal model of the gas is considered. In this model, gases are composed of particles so tiny compared to the volume of the gas that they can be considered zero-volume points in space, and there are no […]
Chemistry • Condensed matter • Materials • Physics • Quantum physics
Minimizing losses in any kind of electronic device is always important, but it is paramount in nanoelectronics. Still, most of the phenomena that lead to inefficiencies in the operation of these nanodevices are poorly understood. Consider the case of quantum dots. A quantum dot is a nanometric crystalline structure of semiconductor materials. In a quantum […]
When two superconducting materials are separated by a very thin (less than 10-8 m or 10 nanometers) layer of an insulating material at very low temperature some peculiar electrical effects can be detected called Josephson effects. If normal conducting metals are separated by such a barrier in that conditions it is possible for a small […]
The current in a semiconductor consists of two parts: the negatively charged electrons in the conduction band and the positively charged holes in the valence band. Although the number of electrons in the conduction band is equal to the number of holes in the valence band, the two contributions to the current are in general […]
In nanophysics one is dealing with physical systems that are formed of parts consisting of a relatively small number of atoms; these systems are typically less than 100 nm in size. As a consequence quantum and surface effects are extremely important. The subject can be traced back to a remarkably visionary and famous talk given […]
Computer science • Condensed matter • Materials • Physics • Quantum physics
When quantum computing comes, it very likely will rely for the fast storage and processing of information on spintronics. Spintronics (from spin transport electronics) is a branch of technology that specifically makes use of quantum-mechanical spin, and especially of the transport of that spin, in electronic devices. Spin is the part of the total angular […]
Quantum mechanics represented a revolution in physics with implications in many other fields like chemistry and biology. It also conducted changes on some of the main scientific lines of thought, including a farewell to determinism. In the science before quantum mechanics probability was accepted only as a lack of knowledge from the system being studied […]
It is likely that you have read somewhere that gravity is much weaker than the electromagnetic interaction. And it is true: for the electron and the proton gravity is 39 orders of magnitude weaker. Still what governs the movement of moons, planets, stars and galaxies is gravity; even the existence of dark matter is deduced […]
As we have discussed in our previous post, there is an important debate in the scientific community regarding the existence of negative absolute temperatures. The debate is not over, and both sides have valuable arguments, but in any case, one thing has already been proved. If negative absolute temperatures are real, the requirement to achieve […]