Possible absence of critical thickness and size effect in ultrathin perovskite ferroelectric films

Peng Gao, Zhangyuan Zhang, Mingqiang Li, Ryo Ishikawa, Bin Feng, Heng Jui Liu, Yen Lin Huang, Naoya Shibata, Xiumei Ma, Shulin Chen, Jingmin Zhang, Kaihui Liu, En Ge Wang, Dapeng Yu, Lei Liao, Ying Hao Chu, Yuichi Ikuhara^*