Self-organized ferroelastic superdomains with enhanced piezoresponse in (101)-oriented Pb(Zr_0.2,Ti_0.8)O₃ thin film

Yu-Chen Liu^1*, Meng-Xun Xie¹, Yu-Huai Li¹, Sheng-Zhu Ho¹, Chin-Han Huang², Min-Yuan Huang², Chun-Wei Huang³, Yi Chou⁴, Chih-Yen Chen⁵, Yi-Chia Chou⁴, Yi-Chun Chen^1,6, Heng-Jui Liu², Jan-Chi Yang^1,6

¹Department of Physics, National Cheng Kung University, Tainan, Taiwan
²Department of Materials Science and Engineering, National Chung Hsing University, Taichung, Taiwan
³Material and Chemical Research Laboratories, Nanotechnology Research Center, Industrial Technology Research Institute, Hsinchu, Taiwan
⁴Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan
⁵Department of Materials and Optoelectronic Science, National Sun Yat-Sen University, Kaohsiung, Taiwan
⁶Center for Quantum Frontiers of Research & Technology (QFort), National Cheng Kung University, Tainan, Taiwan

* Presenter:Yu-Chen Liu, email:bob60734@gmail.com

Through the prorper control of crystalline orientation, strain, thickness and defect density in the thin films, thin film engeering has provided large amounts of degrees of freedom in modifing the physical properties, phase stability and domain architectures of functional materials.
In this study, we controlled the thickness of thin film to provide specific strain in Pb(Zr, Ti)O₃ thin films which were grown on (110)-oriented SrTiO₃ (STO) substrates and revealed a naturally formed superdomain structure appearing in the (101)-oriented tetragonal Pb(Zr,Ti)O₃ epitaxial heterostructure. Different from typical a/c domains, these superdomains are composed of (101)-oriented domains with alternative arrangement of opposite out-of-plane polarizations and have 90^o domain walls in between the conjunction. It is another type of 90^o domain wall that can exist in the low symmetric preferred crystalline orientation. Furthermore, the superdomains present an atypical piezoresponse hysteresis loop with additional intermediate states, corresponding to the switching process of multistate ferroelastic domains.
This work gives a new perspective of the correlation between domain pattern, lattice symmetry, and polarity switching and suggests that not only the typical a/c domain transition but also the elastic deformation of these tiny superdomains can serve as key tunabilities of complex domain engineering.

Keywords: Ferroelectric, Superdomain, PZT, Pulsed laser deposition, Scanning probe microscopy