Premium
A Coherently Strained Monoclinic [111]PbTiO 3 Film Exhibiting Zero Poisson's Ratio State
Author(s) -
Tang Yunlong,
Zhu Yinlian,
Ma Xiuliang,
Hong Zijian,
Wang Yujia,
Wang Wenyuan,
Xu Yaobin,
Liu Ying,
Wu Bo,
Chen Lang,
Huang Chuanwei,
Chen Longqing,
Chen Zuhuang,
Wu Haijun,
Pennycook Stephen J.
Publication year - 2019
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201901687
Subject(s) - materials science , ferroelectricity , heterojunction , monoclinic crystal system , condensed matter physics , epitaxy , pulsed laser deposition , thin film , perovskite (structure) , crystallography , crystal structure , nanotechnology , optoelectronics , dielectric , physics , chemistry , layer (electronics)
[111]‐Oriented perovskite oxide films exhibit unique interfacial and symmetry breaking effects, which are promising for novel quantum materials as topological insulators and polar metals. However, due to strong polar mismatch and complex structural reconstructions on (111) surfaces/interfaces, it is still challenging to grow high quality [111] perovskite heterostructures, let alone explore the as‐resultant physical properties. Here, the fabrication of ultrathin PbTiO 3 films grown on a SrTiO 3 (111) substrate with atomically defined surfaces, by pulsed laser deposition, is reported. High‐resolution scanning transmission electron microscopy and X‐ray diffraction reveal that the as‐grown [111]PbTiO 3 films are coherent with the substrate and compressively strained along all in‐plane directions. In contrast, the out‐of‐plane lattices are almost unchanged compared with that of bulk PbTiO 3 , resulting in a 4% contraction in unit cell volume and a nearly zero Poisson's ratio. Ferroelectric displacement mapping reveals a monoclinic distortion within the compressed [111]PbTiO 3 , with a polarization larger than 50 µC cm −2 . The present findings, as further corroborated by phase field simulations and first principle calculations, differ significantly from the common [001]‐oriented films. Fabricating oxide films through [111] epitaxy may facilitate the formation of new phase components and exploration of novel physical properties for future electronic nanodevices.