Optical vibration modes in spherical multilayer nanostructures

• We study the optical vibration modes in spherical multilayer nanostructures.
• Numerical results for a spherical CdSe/ZnS/CdSe multilayer nanostructure coved by a nonpolar material are obtained.
• 5 branches of IO/SO phonon modes supported by two interfaces and one surface are given and analyzed.
• Dispersion relation of IO/SO phonons and corresponding electron–phonon interaction Hamiltonian is derived.
• Two branches of IO modes with higher frequencies and a SO branch are more important in 5 branches of phonons.

Using the dielectric continuum approach, we study the optical vibration modes in a polar spherical multilayer nanostructure hosted in a non-polar material. The dispersion relation and the corresponding electron–phonon interaction Hamiltonians for interface optical (IO) or surface optical (SO) phonons are derived. As a typical case, the numerical results for the CdSe/ZnS/CdSe spherical multilayer nanostructure are given. The frequency and electric potential characteristics of 5 branches of IO/SO phonon modes are analyzed. The results show that the electron–phonon coupling related to the IO modes with higher frequencies and the SO modes are more significant.