Infrared Dispersion of Second-Order Electric Susceptibilities in Semiconducting Compounds
Infrared Dispersion of Second-Order Electric Susceptibilities in Semiconducting Compounds
复制标题
半导体化合物中二阶电化率的红外色散
DOI：
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发表时间：
1972
期刊：
影响因子：
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通讯作者：
C. Flytzanis
中科院分区：
文献类型：
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作者：
C. Flytzanis
统一研究了半导体化合物在纵向场和横向场下二阶电磁化率${ensuremath{chi}}^{(2)}$的红外行为。先前用于计算晶格共振以上频率的${ensuremath{chi}}^{(2)}$的分子模型被扩展并应用于晶格共振以下频率的${ensuremath{chi}}^{(2)}$的计算。给出了不同贡献的从头计算，并以半经验的方式考虑了局部场修正，与这些材料的宏观红外特性相一致。特别地，对七种半导体InSb、InAs、InP、GaSb、GaAs、GaP和AlSb的拉曼、电光、光整流和远红外频率混合系数进行了明确的考虑。与实验结果吻合较好。讨论了${ensuremath{chi}}^{(2)}$的离子部分与这些化合物中的声子阻尼机制之间的关系，并将Lyddane-Sachs-Teller关系推广到非线性区。在此基础上，用一元完全可溶的$ensuremath{chi}}^{(2)}$ -函数-键模型简要讨论了${ensuremath{chi}} $中不同项与这些化合物中键的共价键的关系。后一种方法结合最近四面体共价化合物成键的现象学描述，也可以推广到II-VI化合物的${ensuremath{chi}}^{(2)}$的计算中。
A unified study is presented of the infrared behavior of the second-order electric susceptibilities ${ensuremath{chi}}^{(2)}$ in semiconducting compounds for both longitudinal and transverse fields. The molecular model used previously for the calculation of ${ensuremath{chi}}^{(2)}$ for frequencies above the lattice resonances is extended and applied to the calculation of ${ensuremath{chi}}^{(2)}$ for frequencies below the lattice resonances as well. An ab initio calculation of the different contributions is given and the local-field corrections are taken into account in a semiempirical way, consistent with the macroscopic infrared properties of these materials. In particular, the Raman, electro-optic, optical rectification, and far-infrared frequency mixing coefficients are explicitly considered for the seven semiconductors InSb, InAs, InP, GaSb, GaAs, GaP, and AlSb. The agreement with experiment is good. The relation between the ionic part of ${ensuremath{chi}}^{(2)}$ and the phonon-damping mechanisms in these compounds is also discussed and a generalization of the Lyddane-Sachs-Teller relation to the nonlinear regime is presented. Further, the relation of the different terms in ${ensuremath{chi}}^{(2)}$ to the covalent character of the bonds in these compounds is briefly discussed in terms of the exactly soluble unidimensional $ensuremath{delta}$-function-bond model. This latter approach combined with the recent phenomenological descriptions of the bonding in tetrahedral covalent compounds can also be extended for the calculation of ${ensuremath{chi}}^{(2)}$ for the II-VI compounds.