三元合金缺陷层对有限超晶格中局域界面光学声子模的影响

Influence of ternary mixed crystal defect layer on the localized interface optical-phonon modes in a finite superlattice

在宏观介电连续近似下,采用转移距阵方法,研究了三元合金缺陷层对有限超晶格中局域界面光学声子模的影响.在这种有限超晶格结构中,可以清楚地看到所有界面模的演化轨迹.结果表明:存在两类局域模,它们的宏观静电势波函数分别局域在缺陷层和表面层附近,且这些模随着超晶格组分层和缺陷层的相对厚度和介电常数的改变,其局域位置和特性发生显著变化.此外,发现虽然能隙中局域模的数目不守恒,但所有界面模的总数守恒.

Within the framework of dielectric continuum theory, we study the effect of ternary mixed crystal defect layer on the localized interface optical-phonon modes in a finite superlattice by using a transfer matrix method. In such a finite superlattice, the evolution of all the interface modes can be clearly tracked. Our numerical results show there exist two types of localized modes and their macroscopic electrostatic potentials mostly locate in the vicinity of the defect layer or surface layer, respectively. As the relative widths and nature of the structural cell or the defect layer are altered, the localized characteristics of these modes are significantly influenced. Though the conservation of the total number of localized modes is broken, the conservation of the total number of all interface modes including both the extended modes and localized modes is still kept for every value of the wavevector qⅡ.