Category archives: Quantum physics

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 […]

Imagine a military regiment in formation. That we will call symmetry. Now imagine the same regiment when it is dismissed by the commanding officer: at once the soldiers disperse and tend to form domains (groups) or pairs. Hence, we can say that the symmetry is spontaneously broken. Both superconductors and ferromagnets are examples of electron […]

Few materials have drawn as much attention as graphene, it fascinating attributes such as one-atom thickness and relativistic electrons, and its technological properties like transparency, large mechanical strength, and ultra-high electron’s mobility, position it as one of the more promising materials in the present. Recently, simultaneous experimental and theoretical studies have confirmed that combining graphene […]

Mobile phones and computers are currently responsible for up to 8% of the electricity use in the world. This figure has been doubling each past decade but nothing prevents it from skyrocketing in the future. Unless we find a way for boosting energy efficiency in information and communications technology, that is. An international team of […]

Imagine that we have a conductor or a semiconductor through which a current is flowing. Then we apply a strong transverse magnetic field. As a result, we can measure a potential difference at right angles to both the current and the field caused by the deflection of charge carriers by the field. This effect was […]

The revolutionary theory of topological quantum chemistry , a description of the universal global properties of all possible band structures and materials, diagnoses topological phases based on elementary band representations. A set of bands is topological if it lacks an “atomic limit” that obeys the crystal symmetry (and time reversal, if desired): formally, an atomic […]

Chemists have a range of different spectroscopic techniques to study organic molecules. All of these techniques are based on spectra generated by a range of electronic transitions and vibrations, key excitations in matter, the study of which provides information about characteristics of materials and, therefore, allow their identification. In this context, one of those spectroscopic […]

The properties of bismuth have long defied classification, placing it in a category of its own. Now, as if it was not enough, it turns out its electronic structure has higher-order topology. This has been shown by an international team with the participation of Maia G. Vergniory (DIPC, Ikerbasque, UPV/EHU) and coordinated by Titus Neupert […]

Atom scattering at low energies has a long history as a useful probe of surface properties. The most common atomic projectiles are helium atoms formed into a monoenergetic beam directed toward the surface with energies in the thermal range, meaning kinetic energies less than 100 meV. From ordered surfaces the scattered spectra consist of sharp […]

The wave nature of light expresses itself in the propagation all over space, showing an intrinsic limitation to be localized beyond the so-called diffraction limit which is of the order of half the wavelength of the photons propagating. However when interacting with matter, light often gets reflected, diffracted, scattered or absorbed depending on the interactions […]