Phonon anomalies and structural instabilities in TbScO3 (MERLIN)

Distorted perovskite TbScO3 is a particularly interesting lanthanide scandate, exhibiting a dramatic flexoelectric effect, along with the common features of the wider family of lanthanide scandates. Accurate knowledge of its structure and dynamics is of particular importance, for example due to its use as a substrate for epitaxial growth of high-quality perovskite thin films. However, the structure and dynamics of this material at low temperatures are not properly understood. We plan to investigate these by combining phonon studies with powder and single crystal neutron diffraction. Powder diffraction on HRPD and single crystal diffraction on SXD will be used to study structural models and characterise subtle distortions of this material. Phonon spectrometry on MERLIN – preceded by careful phonon characterization using CASTEP with Horace and the Euphonic package – will be used to clarify discrepancies between phonon modes allowed by symmetry and those previously experimentally observed.