Mechanism of Photoinduced Dielectric Response in Ferroelectric Sr1-xCaxTiO3
Mechanism of Photoinduced Dielectric Response in Ferroelectric Sr1-xCaxTiO3
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DOI：
10.1143/jpsj.77.054704
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发表时间：
2008-04
影响因子：
1.7
通讯作者：
Y. Yamada;Koichiro Tanaka
中科院分区：
文献类型：
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作者：
Y. Yamada;Koichiro Tanaka
研究了Sr 1-xCaxTiO 3（SCT）铁电体在光激发下的介电响应.我们观察到光致德拜色散，这是类似于名义上纯SrTiO 3中观察到的。SCT中光致德拜色散的温度依赖性表明，光致德拜色散的起源是导电区和绝缘区之间的界面极化。我们假设具有移动的光生载流子的导电区域部分由光激发产生，并表明导电区域模型很好地再现了实验结果。我们还观察到光诱导铁电相变温度的降低。这可以用移动的光生载流子的屏蔽效应减少了钙诱导偶极子之间的库仑相互作用来定量解释。
The dielectric response of ferroelectric Sr 1- x Ca x TiO 3 (SCT) under photoexcitation has been investigated. We observed photoinduced Debye dispersion, which is similar to that observed in nominally pure SrTiO 3 . The temperature dependence of photoinduced Debye dispersion in SCT indicates that the origin of photoinduced Debye dispersion is the interfacial polarization between conductive and insulative regions. We assumed that conductive regions with mobile photocarriers are partly generated by photoexcitation and showed that the experimental results are well reproduced by the conductive-region model. We also observed a photoinduced reduction in ferroelectric phase transition temperature. This can be quantitatively explained by the reduction of Coulomb interaction between Ca-induced-dipoles due to the screening effect by mobile photocarriers.