A direct insight into ferroelectricty under pressure by X-ray absorption spectroscopy

The overarching aim of this project is to re-examine the general issue of breaking of inversion symmetry at extreme pressures. We focus here on the model ferroelectric perovskite PbTiO3. The approach is to use X-ray absorption spectroscopy to probe the local environment of the Pb and Ti cations and look for direct proofs of off-centring at high pressures. Measurements will be carried out up to 100 GPa, at room temperature and at 15 K for a more relevant comparison with first-principle calculations. Together with our recent infrared spectroscopy data, this is expected to provide new insight on the reality of ferroelectricty under pressure.