One of our primary focus areas is how local structural correlations in piezoelectric materials relate to the physical properties of the materials.

Piezoelectric relaxor materials, are materials that directly couple electrical and mechanical energy in the solid state; i.e. applying an electric field will cause a mechanical deformation and vice versa. The electromechanical coupling in piezoelectric materials makes them very useful in a range of important technologies such as sensors , highly precise actuators, and ultrasonic transducers which are e.g. essential in medical imaging. A fundamental understanding of how the complex atomic and nanoscale structures are linked to the properties is still lacking, thus making rational design impossible.

The central challenge is that these materials are highly disordered on the atomic and nanoscale, but this disorder is not random, it is correlated. It is generally accepted that the piezoelectric properties are determined by this correlated disorder, however their structure and role in piezoelectric properties are still controversial.

To move forward, we thus need to understand the structure on different length scales: the local structure (few atoms to a few unit cells) that often show a distorted and lower symmetry compared to the long range average structure (many unit cells), the atomic correlations on the nanoscale, and the long range structure. No single experimental technique can give accurate structural information for all of these length-scales, and thus it is imperative to combine data from different experiments in a common model that captures the details across the length-scales of interest.