Chemical trends in high-Tc ferroelectricity and superconductivity

High temperature ferroelectrics and superconductors show strong localization on quantum structural diagrams constructed to organize the full database of intermetallic compounds according to local structure. Furthermore, there is a strong diagrammatic relationship between ferroelectrics and superconductors. These regularities support the idea that both phenomena originate in chemical factors which can be related to lattice instability and anharmonicity. In addition, they provide a sound basis for the future development of diagram-based strategies for the identification of promising new candidate materials for high-Tc ferroelectricity and superconductivity.