一类耦合超晶格系统中的电子局域态(英文)

Localized Electronic States in a Class of Coupled Superlattices

理论研究了一类耦合超晶格系统中的电子局域态 ,该系统是由两个半无限 Ga As/Al As超晶格通过隔离层 Aly Ga1-y As耦合而成 .数值计算表明 y=1时系统仍存在局域态 ,但要求隔离层的厚度比规则垒层的厚度小许多 .比较了只有一个阱层厚度不规则的不规则超晶格系统的局域态和耦合超晶格中局域态的区别 ,发现后者存在两支局域模 ,分别对应于偶宇称态和奇宇称态 ,而在相同参数下 ,前者仅存在偶宇称态 .

Theoretical investigation of the localized electronic states of GaAs/AlAs superlattice coupled via an Al y Ga 1-y As spacer layer is presented.Numerical computations have shown that the electrons can also be localized when y=1 ,but only for the case that the spacer layer thickness is much more smaller than the regular barrier thickness. A comparison between the localized states duo to barrier width change (for the coupled superlattice system when y=1 ) and the localized states caused by well width difference ( for an irregular superlattice with only one well perturbed in width ) is given and we have found that ,with the used parameters, there exist two branches of localized state modes in the coupled superlattice corresponding to even and odd states respectively, but the irregular superlattice has only even localized state modes. The reason is also discussed.