Cryogenic crystal phase of ferroelectric SrTiO3

In this proposal, we aim to investigate the crystal phase and strain of thin-film SrTiO3 (STO) at cryogenic temperatures and
compare these properties with those of the bulk crystal. Our recent experiments have verified the occurrence of ferroelectricity in these films
below approximately 100 K, resulting in a record-high cryogenic Pockels coefficient in any thin-film material. Strain plays a crucial role in the
paraelectric-to-ferroelectric phase transition in perovskites. Understanding its effect in thin films is essential to optimize the Pockels
coefficient by strain engineering. Additionally, we plan to explore the impact of an applied electric field on the crystal structure at these low
temperatures. This project will provide valuable insights into the cryogenic behavior of the biased ferroelectric crystal structure, which is
critical for advancing the field of electro-optic device applications.