Intrinsic- strain- induced ferroelectric order and ultrafine nanodomains in SrTiO3

• 成果类型: Article
• 署名作者: Zhang, Peixi; Li, Qiang; Li, Zhiguo; Shi, Xiaoming; Wang, Haoyu; Huo, Chuanrui; Zhou, Lihui; Kuang, Xiaojun; Lin, Kun; Cao, Yili; Deng, Jinxia; Yu, Chengyi; Chen, Xin; Miao, Jun; Xing, Xianran
• 署名单位: University of Science & Technology Beijing; University of Science & Technology Beijing; University of Science & Technology Beijing; East China University of Science & Technology; East China University of Science & Technology; Guilin University of Technology
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-14910
• DOI: 10.1073/pnas.2400568121
• 发表日期: 2024-06-18
• 页码: 1-7
• 关键词: room-temperature ferroelectricity; 1st-order raman-scattering; phase-transitions; polarization; expansion

摘要

Nano ferroelectrics holds the potential application promise in information storage, electro- mechanical transformation, and novel catalysts but encounters a huge challenge of size limitation and manufacture complexity on the creation of long- range ferroelectric ordering. Herein, as an incipient ferroelectric, nanosized SrTiO3 was indued with polarized ordering at room temperature from the nonpolar cubic structure, driven by the intrinsic three- dimensional (3D) tensile strain. The ferroelectric behavior can be confirmed by piezoelectric force microscopy and the ferroelectric TO1 soft mode was verified with the temperature stability to 500 K. Its structural origin comes from the off- center shift of Ti atom to oxygen octahedron and forms the ultrafine head- to- tail connected 90 degrees nanodomains about 2 to 3 nm, resulting in an overall spontaneous polarization toward the short edges of nanoparticles. According to the density functional theory calculations and phase- field simulations, the 3D strain- related dipole displacement transformed from [001] to [111] and segmentation effect on the ferroelectric domain were further proved. The topological ferroelectric order induced by intrinsic 3D tensile strain shows a unique approach to get over the nanosized limitation in nanodevices and construct the strong strain- polarization coupling, paving the way for the design of high- performance and free- assembled ferroelectric devices.