SPIn-based logic GAtes with topological insulators

The SPIGA project explores a new generation of ultra-low-power logic devices, in which information is processed by exploiting not only charge, but also the spin degree of freedom of electrons. In a context where the energy efficiency of electronics is becoming an increasingly stringent constraint, the project proposes a “more-than-Moore” approach based on spin-orbitronic phenomena and emerging materials.

At the core of the idea is to exploit the presence of surface states with spin–momentum locking in topological insulators (TIs), which makes it possible to convert a spin accumulation into a measurable change in electrical resistance. SPIGA aims to demonstrate and quantify this effect in TI/semiconductor heterostructures, with the goal of realizing a scalable logic gate operating at room temperature.

To ensure compatibility with microelectronics, the project aims to integrate TIs on group-IV semiconductor platforms, controlling growth, interface quality, and the position of the Fermi level near the Dirac point to maximize the contribution of surface states. The logic functionality will be achieved by modulating the resistance between source and drain through spin injection into the semiconductor, initially using optical schemes to validate the physical mechanisms, and subsequently using fully electrical architectures oriented toward integration. The ultimate ambition is to demonstrate an efficient and reproducible logic “building block”, based on TI/semiconductor heterostructures and controlled spin-to-charge interconversion.