Imagine a material in which electrons can be 1000 times heavier than usual. Imagine that the electrons in these material move 100 times slower than in a normal metal, and become superconducting at a very low temperature. These materials have existed for 30 years and have been at the origin of new surprises. They are called “Heavy-Fermion compounds”.
Despite the “weight” of their electrons, heavy fermions are always good electricity conductors. They can even become superconductors with extraordinary properties. These properties are sometimes unique in the history of superconducting materials.
Researchers discovered superconductivity in heavy fermions at a very low temperature. They have to be cooled very close to absolute zero, sometimes less than a tenth of a kelvin from absolute zero. But if we compare their critical temperature depending on the temperature (energy) of the electrons that carry the current rather than on the room temperature, it seems amazingly hot !
