DESIQM · Designer superconductivity in interacting quantum metamaterials

Designer superconductivity in interacting quantum metamaterials

Transitioning to renewable energy sources is crucial for combating climate change. However, these sources are often located in remote locations, far away from the bustling urban centres with the highest energy demands. Meanwhile, the mass adoption of electric vehicles is necessary for reaching emission targets but exacerbates urban energy demand, creating a bottleneck for clean power. Consequently, achieving a sustainable future presents a hidden challenge: how can we efficiently transport clean electricity over long distances? Conventional power grids lose significant energy during long-distance transmission (8-15%) and rely on bulky copper wires requiring considerable space. Superconducting wires, with zero electrical resistivity, could overcome this limitation. A superconducting power grid would completely eliminate the energy lost during transmission and require much less space compared to traditional copper grids (80% more compact). However, conventional superconductors require extremely low temperatures achievable only with expensive liquid helium cooling, making them impractical for widespread use. Some materials exhibit unconventional superconductivity at higher temperatures, allowing them to operate with cheaper liquid nitrogen. However, their operating temperatures remain too low for large-scale power grid integration. The overall objective of the project is to advance the viability of unconventional superconductors by creating “designer superconductors”. The key characteristic of unconventional superconductors is that their electrons interact strongly with one another. But this behaviour is hard to anticipate, and unconventional superconductors are often discovered more by chance than by design. The DESIQM project explored a new design-first approach for the bottom-up fabrication of custom unconventional superconductors with strong electron interactions, called “interacting quantum metamaterials”. These quantum metamaterials are constructed by moving individual atoms or molecules with a scanning tunnelling microscope to create a pattern that modifies surface electron behaviour. The project proposed a quantum metamaterial on the surface of a topological Kondo insulator, which already hosts strongly interacting surface electrons—the key ingredient of unconventional superconductors. However, finding atoms to effectively manipulate these electrons was a challenge. The project's major conclusion is the identification of “Kondo holes” – a class of atoms ideally suited for fabricating quantum metamaterials on topological Kondo insulators. This discovery paves the way for developing efficient, high-temperature designer superconductors that could revolutionize clean energy transmission for a sustainable future.

Data: CORDIS, © European Union