Confined optical phonons in semiconductor quantum dots

The continuum dispersive hydrodynamic (HD) theory is employed to study the confinement of optical phonons in a spherical quantum dot. To satisfy both the HD mechanical and the electromagnetic (EM) boundary conditions, we incl ude an interface polariton (IP) component in addition to the LO vibration. It is found that the IP component has remarkable effect on the phonon assoc iated electrical potential, and consequently will influence the electron ph onon coupling strength in quantum dots. We also show that the eigenmode wit h interface LO vibration does not exist in quantum dots, while it possibly exists in other low-dimensional systems. Other confinement features are dis cussed comparatively as well. (C) 1999 Elsevier Science Ltd. All rights res erved.