Hybrid improper ferroelectricity in (Sr,Ca)₃Sn₂O₇ and beyond: universal relationship between ferroelectric transition temperature and tolerance factor in n=2 Ruddlesden-Popper phases

Suguru Yoshida, Hirofumi Akamatsu, Ryosuke Tsuji, Olivier Hernandez, Haricharan Padmanabhan, Arnab Sen Gupta, Alexandra S. Gibbs, Ko Mibu, Shunsuke Murai, James M. Rondinelli, Venkatraman Gopalan, Katsuhisa Tanaka, Koji Fujita^*

^*Corresponding author for this work