Dynamical effective charges in semiconductors: A pseudopotential approach
Dynamical effective charges in semiconductors: A pseudopotential approach
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DOI：
10.1088/0022-3719/11/2/011
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发表时间：
1978-01
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影响因子：
--
通讯作者：
P. Vogl
中科院分区：
文献类型：
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作者：
P. Vogl
在赝势理论的框架下，提出了部分共价半导体中横向动力学有效电荷Z*的从头计算方法。它基于先前建立的Z*在晶体的反微观介电函数方面的表达式，但绕过了后者的直接反转。与早先的计算不同，计算结果对边界完全不敏感。此外，表示电荷中性的声学求和规则是内在保证的。在局域经验赝势方法中，进行了简单的解析模型计算，并与键轨道模型进行了比较，同时进行了全数值计算。对于III-V化合物，由此得到的Z*低估了实验有效电荷约30%，而对于II-VI材料，得到了很好的一致性。讨论了这些发现的原因，并估计了几种改进的效果。
A method for an ab-initio calculation of transverse dynamical effective charges Z* in partially covalent semiconductors within the framework of pseudopotential theory is presented. It is based on previously established expressions for Z* in terms of the inverse microscopic dielectric function of the crystal but circumvents the direct inversion of the latter. In contrast to earlier calculations the results are definitely boundary insensitive. Moreover, the acoustic sum rule expressing charge neutrality is inherently guaranteed. Within the local empirical pseudopotential method a simple analytical model calculation, which is compared with the bond orbital model, as well as a full numerical computation is performed. For III-V compounds the resulting Z* underestimate the experimental effective charges by approximately 30% while good agreement for II-VI materials is obtained. Reasons for these findings are discussed and the effects of several refinements are estimated.