Department of Materials Science and Engineering and Materials Science Program, University of Wisconsin, Madison, Wisconsin 53706, USA.
Phys Rev Lett. 2010 May 21;104(20):207601. doi: 10.1103/PhysRevLett.104.207601. Epub 2010 May 19.
The origin of the functional properties of complex oxide superlattices can be resolved using time-resolved synchrotron x-ray diffraction into contributions from the component layers making up the repeating unit. The CaTiO3 layers of a CaTiO3/BaTiO3 superlattice have a piezoelectric response to an applied electric field, consistent with a large continuous polarization throughout the superlattice. The overall piezoelectric coefficient at large strains, 54 pm/V, agrees with first-principles predictions in which a tetragonal symmetry is imposed on the superlattice by the SrTiO3 substrate.
利用时间分辨同步加速器 X 射线衍射，可以将钙钛矿/钛酸钡超晶格中钙钛矿层的压电响应分解为组成重复单元的各层的贡献。钙钛矿/钛酸钡超晶格的钙钛矿层对施加的电场具有压电响应，这与超晶格中整个连续的大极化一致。在大应变下的整体压电系数为 54 pm/V，与第一性原理预测相符，即 SrTiO3 衬底对超晶格施加四方对称。
