New innovative devices, such as resistive memories (ReRAM) that store data by changing their resistance, faster and with lower consumption when compared to traditional methods. But also low-energy electrical switches to reduce electronics consumption and thus improve the performance of computing and memory systems. There are many applications of a new Italian discovery which has shown how the so-called ‘Mott materials’ – i.e. a type of insulators fundamentally different from conventional insulators, capable of passing from the insulating to the conductive state – can change state precisely because of the topological defects in their crystalline structure.
“We have seen – Claudio Giannetti, coordinator of the study and director of the Interdisciplinary Advanced Physics of Materials laboratories at the Department of Mathematics and Physics of the Catholic University of Brescia, tells Adnkronos – that theThe transformation did not occur randomly, but at a precise point called a topological defect, that is, when the material is insulating it forms geometric structures that follow very precise mathematical rules, an intrinsic defect in the structure of the material itself.”. The study was carried out together with the Imdea Nanociencia foundation of Madrid, the Belgian KU Leuven, the Sissa of Trieste and the Diamond Light Source, an English synchrotron, and published in the journal ‘Nature Communications’. The research was conducted specifically on a particular vanadium oxide (V₂O₃) which showed how it is precisely these defects that trigger the transition. The experiment that led to the discovery was carried out at the Diamond Light Source in the United Kingdom.
“We took the light of the synchroton – explains Giannetti – and focused it so as to see the emitted electrons, and then passed them to microscopy”. The researchers were able to see how the transformation from insulator to conductor did not occur randomly, but at the moment of the topological defect: “Now that we know that it is the topological defect that drives the phenomenon, new experiments can be designed to fix defects and control the resistive switching processwith the aim of obtaining complete control of the process and engineering devices capable of operating at unprecedented speeds and with extremely low power dissipation” urges the professor.
These materials are synthesized starting from the atoms that compose them with techniques that allow the creation of an extremely thin crystal of pure material. “Resistive switching is the fundamental process underlying the sudden change in electrical properties in solid-state devices under the action of intense electric fields” underlines Alessandra Milloch of the Catholic University of Brescia and first author of the work. “Despite its technological relevance, this process was thought to be stochastic in nature, driven by local and uncontrollable fluctuations. We decided to delve deeper and investigate the true nature of this phenomenon in planar devices consisting of two metal contacts deposited on a thin film of V2O3, which is one of the most famous examples of Mott insulator.”
The devices that could be made would improve efficiency and performance in computing and memory systems, with multiple applications ranging from computers to advanced artificial intelligence systems. For Giannetti, the idea of neuromorphic materials represents “the future of electronics.”
