The results of the international superconductor research have landed in ‘Science’ at room temperature, the material which could revolutionize technologies, reducing the energy costs of electricity distribution and change the very structure of the electricity production and distribution system in the world. In fact, the study makes less mysterious is the ‘strange’ behavior of cuprates, superconducting materials composed of copper, oxygen and other elements which however ‘work’ only at very low temperatures. This opens the way to a real electricity revolution.
Scientists from the Chalmers University of Gothenburg, the Polytechnic University of Milan, the Sapienza University of Rome and the European Synchrotron ESRF in fact, they discovered that, in the normal state, the presence of charge density waves modifies the ‘strange metal’ behavior of cuprates and leads it to be more similar to that of normal metals. Superconductors are materials in which electric current travels without resistance below a certain temperature.
This, explain the Polytechnic of Milan and the Chalmers University, “differentiates them drastically from normal metals in which resistance involves a production of heat and therefore a waste of energy when a current flows “. Although known for more than a century, superconductivity remains one of the most mysterious and fascinating phenomena studied by the physics of solids. And the researchers’ goal is precisely to find materials that are superconducting at normal temperatures.
The scholars of the PoliMi and of the University of Chalmers recall that “an important property of cuprates – given by the fact that, even at a temperature above the critical one, when they are in the ‘normal’ state and therefore have no zero resistance – they behave in an unconventional way, so much so that they are referred to as’ strange metals‘”. And” the oddity – they continue – lies in the linear increase in resistivity with temperature, which is not usually the case for normal metals “. Understanding the ‘strangeness’ of the ‘normal’ state of superconducting cuprates is one of the goals of international research in this field in recent years.
“This kind of observation is of great relevance because it finally shows a correlation between macroscopic properties (resistivity in the normal state, superconductivity) and microscopic properties (the charge density waves) “explains Professor Giacomo Ghiringhelli, professor of Experimental Physics at the Milan Polytechnic.” This – he adds – may be the key to the problem long sought by theorists, a secure basis on which to finally build the explanation of the very original behavior of superconducting cuprates “.
To understand the importance of this, experts invite us to consider that “superconductivity is the most spectacular macroscopic manifestation, visible to the naked eye, of quantum physics, indispensable for describing phenomena on the atomic scale, but usually not on the macroscopic one. However, superconductivity is a macro-quantum phenomenon. Now it turns out that even at high temperatures, in the ‘normal’ state, cuprates have a quantum behavior, so we can speak of ‘ultra-quantum’ matter “.