论文标题
在强耦合铁电/电介质超晶格的介电组件中，光诱导的皮秒晶格压缩
Optically Induced Picosecond Lattice Compression in the Dielectric Component of a Strongly Coupled Ferroelectric/Dielectric Superlattice
论文作者
论文摘要
铁电/介电BATIO3/CATIO3超晶格的频秒高度触发光激发导致结构响应，这是组件层之间强静电偶联的结果。时间分辨X射线自由电子激光衍射表明，对光学激发的结构响应包括与光激发荷载载流子驱动的去极化场筛选一致的超晶格的净晶格膨胀。去极化场筛选驱动的膨胀与从底部电极发射的光声脉冲分开，超晶格在该底部的外延生长。超晶格X射线反射的衍射强度的分布表明，去极化场筛选诱导的应变包括铁电batio3中的光诱导膨胀和Catio3的收缩。 BATIO3层中膨胀的大小大于CATIO3的收缩。 BATIO3和CATIO3组件中去极化场筛分驱动的应变的大小差异可能是由于Batio3/Catio3接口对Catio3极化的氧气八人体旋转模式的贡献。 CATIO3层中的去极化场筛选驱动的极化降低指向一个新的方向，以操纵强耦合的铁电/介电超晶格的组分层中极化。
Above-bandgap femtosecond optical excitation of a ferroelectric/dielectric BaTiO3/CaTiO3 superlattice leads to structural responses that are a consequence of the screening of the strong electrostatic coupling between the component layers. Time-resolved x-ray free-electron laser diffraction shows that the structural response to optical excitation includes a net lattice expansion of the superlattice consistent with depolarization-field screening driven by the photoexcited charge carriers. The depolarization-field-screening-driven expansion is separate from a photoacoustic pulse launched from the bottom electrode on which the superlattice was epitaxially grown. The distribution of diffracted intensity of superlattice x-ray reflections indicates that the depolarization-field-screening-induced strain includes a photoinduced expansion in the ferroelectric BaTiO3 and a contraction in CaTiO3. The magnitude of expansion in BaTiO3 layers is larger than the contraction in CaTiO3. The difference in the magnitude of depolarization-field-screening-driven strain in the BaTiO3 and CaTiO3 components can arise from the contribution of the oxygen octahedral rotation patterns at the BaTiO3/CaTiO3 interfaces to the polarization of CaTiO3. The depolarization-field-screening-driven polarization reduction in the CaTiO3 layers points to a new direction for the manipulation of polarization in the component layers of a strongly coupled ferroelectric/dielectric superlattice.
