Electric field induced charge density variations in partially-ionic compounds
Electric field induced charge density variations in partially-ionic compounds
复制标题
电场引起部分离子化合物中电荷密度的变化
DOI：
10.1016/s0022-3697(01)00169-x
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发表时间：
2001
影响因子：
4
通讯作者：
A. Pucher
中科院分区：
文献类型：
--
作者：
U. Pietsch;J. Stahn;J. Davaasambuu;A. Pucher
采用调制技术和同步辐射技术，分别研究了沿着[111]和[11.0]方向外加强电场E时，立方相ZnSe和三角相SiO2中电荷密度的变化.选择特别弱的反射，我们观察到积分强度与E的几乎线性变化，在200 ℃时变化高达2%。|E|对于这两种晶体，单位晶胞内的相对离子位置的位移超过单位晶胞参数的压电诱导变化至少一个数量级。所测量的强度变化的ZnSe可以解释由相反的位移的锌和硒离子朝向场的方向打破了僵硬的四面体协调的化学键。对于石英，电场仅在O-Si键与电场方向倾斜的地方引发这些氧离子的位移。其他氧离子和硅的位置几乎保持不变。因此，离子排列主要通过O-Si-O键角的变化来描述。
Using a modulation technique and synchrotron radiation, we investigated the charge density variations in cubic ZnSe and trigonal SiO2induced by an external high-electric field E applied along the [111] and [11.0] direction, respectively. Selecting particularly weak reflections, we observed an almost linear variation of the integrated intensity versus E changing by up to 2% at |E|=3kV/mm. For both crystals, the displacements of the relative ion positions within the unit cell exceed the piezoelectric induced variation of the unit cell parameters by at least one order of magnitude. The measured intensity variations of ZnSe can be explained by the opposite displacement of the zinc and selenium ions towards the field direction breaking the stiff tetrahedral coordination of the chemical bond. For quartz, the electric field initiates a displacement of those oxygen ions only where the O–Si bond is directed oblique to the field direction. The other oxygen ions and the silicon positions remain nearly unchanged. Thus, the ionic arrangement is described mainly by a change in the O–Si–O bonding angles.