Effects of ternary mixed crystals on interface/surface optical phonon in spherical core-shell quantum dots

摘要

Within the framework of the dielectric continuum approach and modified randomelement-isodisplacement model, the optical vibration mode in a spherical core-shell quantum dot (CSQD) consisting of ternary mixed crystals (TMCs) are investigated. The dispersion relation and electron-phonon interaction Hamiltonian are derived. As a typical case, the numerical results for ZnS/ZnxCd1-xS and GaAs/AlxCa1-xAs CSQDs are obtained and discussed. Taking the one- and two-mode behaviors of TMCs into account, the effects of TMCs on interface/surface optical (IO/SO) phonon show that there are 3 and 5 branches of IO/SO phonon modes in ZnS/ZnxCd1-xS and CaAs/AlxCa1-xAs CSQDs for a given component of TMC, respectively. It is also found that the IO/SO phonon frequencies and electron-phonon interactions are strongly dependent on the component of TMCs and the size of CSQDs. We hope this work would be useful for the study of the phonon-related photoelectric properties in CSQDs consisting of TMCs.