Silver(II) fluoride is a strongly correlated insulator, with characteristics remarkably similar to those of parent high-temperature superconducting cuprates but also significant differences. To quantify the degree of similarity between the two families of materials in terms of parameters has been one of the aims of the project. The similarities with cuprates suggest that AgF2 has the potential to be the basic building block to a new class of strongly correlated materials with similar properties. Since high temperature superconductors have a large field of applications, it is possible that superconductors based on silver fluorides can also find a niche. Furthermore, finding a new superconductor with similar characteristics as those of cuprates can help solve several remaining mysteries of their mechanism.
The purpose of SILVERPATH was to develop appropriate models to characterize and predict magnetic, metallic and superconducting properties of silver fluorides and related materials by combining analytical and computational methods. In doing so, we have fostered a strong collaboration with the chemist group of W. Grochala (Warsaw). This has strengthened the transfer of knowledge between condensed matter physics and chemistry communities.
We have significantly advanced in understanding the electronic properties of bulk AgF2 by developing appropriate models and realistic parameters. The strength of correlations in bulk AgF2 has been thoroughly studied, which allows us to classify the material as a charge-transfer correlated insulator, confirming the material is a cuprate analogue. A route for charge doping flat monolayer AgF2 in a chemical capacitor setup has been found and studied, working in close collaboration with the chemistry group at Warsaw. The electron doping path has been found particularly promising in terms of control of doping and superconductivity.
A very promising new route to superconductivity has also been explored in related quantum materials, where the interaction is mediated by the coupling to polar fluctuations instead of spin fluctuations. An example of possibly relevant materials are SrTiO3, KTaO3 and related oxide heterostructures. We have also significantly advanced in understanding the coupling to polar fluctuations in these systems by developing appropriate models and realistic parameters. These materials are very interesting because they have both a ferroelectric and a superconducting phase, which may lead to interesting possibilities to control superconductivity and potential applications in devices.
