The term “Andreev states” is used to describe the energy levels present within a given material that exhibits both magnetic flux and channel transmission. In short, this electronic configuration has been found to allow non-superconducting materials to conduct a “supercurrent,” which eliminates the possibility of electron resistance from occurring within the material.
Andreev states are present within superconductors, which therefore account for their impressive ability to maintain their electricity conductance without the presence of such resistance.
In an effort to investigate the properties of exotic particles, particularly Majorana fermions, a group of researchers from the Massachusetts Institute of Technology (MIT) led by Landry Bretheau, sandwiched graphene between two superconductors and analyzed its electronic properties.
While Andreev states spectroscopy analyses have only been performed in a few systems, such as silver wires, it has never before been considered as an important property in two-dimensional materials, such as graphene. As one of the most notable 2D materials, graphene, a single-atom thick sheet of carbon atoms, will exhibit a normal movement of electrons, enabling the team of physics to easily study the Andreev states present within the materials.