Optical Phonon Modes And Electron-phonon Interaction In Core-shell Quantum Dots Consisting Of Ternary Mixed Crystals

Using a dielectric continuum model and a modified random-element isodisplacement model,the effect of ternary mixed crystal?TMC?of optical phonon models in core-shell quantum dots?CSCD?is studied.Firstly,the dispersion relation of interface/surface optical?IO/SO?phonon is investigated.Numerical calculations are performed for.several typical CSCD consisting of TMC.The results revealed that there are five branches of IO/SO phonon modes in GaAs/Al_xGa_1-xAs and ZnS/ZnS_xSe_1-x systems,and three branches modes in ZnS/Zn_xCd_1-x and InN/In_xGa_1-xN systems.The effects of one mode and two mode behaviors of the TMC on the phonon modes are also discussed.Every branches of IO/SO phonon change nonlinearly with composition x.We also found that the sensitivity of the IO/SO phonon frequencies are decreasing with the increasing shell thickness and the ternary mixed effects have more important influence on the optical phonon frequencies for the small quantum number l.Then,the corresponding electron-IO/SO phonon interaction have been studied.The results revealed that the composition x has more important influence on electron-phonon interaction.The smaller l has more significant contribution to the electron-phonon interaction.It is also found that dielectric constant?d has important influence on the phonon potentials.