The Transverse Effective Charge of the IV–VI Compound Semiconductors

抄録

Littlewood’s assumption in the calculation of the transverse effective charge (TEC) of IV–VI compound semiconductors is studied by the simple calculation at W-point on the Jones zone surfaces based on the Heine-Jones model. It is shown that the main peak of optical absorption spectrum cannot be assigned only to (111) component of the effective charge in contrast with Littlewood’s assumption. The TEC is directly calculated by executing the band calculation with the potential obtained by the EPM in the framework of Vogl’s expression. The calculated result gives better agreement with experiment than Littlewood’s. The acoustic sum rule is also studied by using the similar formulation given by Vogl.