Structural phase transitions in perovskite compounds based on diatomic or multiatomic bridges

The structural phase transitions in perovskite compounds were revived in the past decade by the emergence of a large number of perovskite compounds based on diatomic or multiatomic bridges, e.g. CN-, N-3(-), HCOO-, SCN-, and N(CN)(2)(-), with various interesting properties for possible applications such as in dielectric switches, ferroelectrics, and multiferroics. Compared with the well-studied perovskite oxides and halides, these new perovskite compounds with larger bridges give rise to an increase in the complexity of structural variations as well as an opportunity to tailor the physical properties by taking advantage of the designable and tunable characteristics of the metal species, bridging ligands, and guest cation components. Here, we highlight the recent advances on the thermally-induced structural phase transitions of the perovskite compounds based on the diatomic or multiatomic bridges, focusing on the important role of the components in the phase transition behaviours as well as the intrinsic switching behaviours of physical properties.