標題: Atomic-scale mechanism of internal structural relaxation screening at polar interfaces
作者: Li, Mingqiang
Cheng, Xiaoxing
Li, Ning
Liu, Heng-Jui
Huang, Yen-Lin
Liu, Kaihui
Chu, Ying-Hao
Yu, Dapeng
Chen, Long-Qing
Ikuhara, Yuichi
Gao, Peng
材料科學與工程學系
Department of Materials Science and Engineering
公開日期: 25-五月-2018
摘要: The effective screening of the polarization bound charge is a prerequisite to stabilize the ferroelectricity in ferroelectric thin films. Here, by combining annular bright field imaging and electron energy-loss spectroscopy (EELS) in an aberration-corrected scanning transmission electron microscope with phase-field simulations, we investigate the screening mechanism by quantitatively measuring the structural relaxation at Pb(Zr0.2Ti0.8)O-3/SrTiO3 interfaces. We find that the thickness of the interfacial layer is similar to 3.5 unit cells (similar to 1.4 nm) in a domain with upward polarization and similar to 5.5 unit cells (similar to 2.2 nm) in a domain with downward polarization. Phase-field simulations, an EELS analysis, and a lattice parameter analysis verify the existence of interfacial oxygen vacancies accounting for the narrower interfacial layer in the domain with upward polarization. Our study indicates the internal structural relaxation at the interface is the dominant mechanism for the polarization charge screening for ferroelectric films grown on insulating substrates and has implications for our understanding of domain switching in ferroelectric devices.
URI: http://dx.doi.org/10.1103/PhysRevB.97.180103
http://hdl.handle.net/11536/145029
ISSN: 2469-9950
DOI: 10.1103/PhysRevB.97.180103
期刊: PHYSICAL REVIEW B
Volume: 97
顯示於類別:期刊論文