Properties of optical bipolaron in symmetric quantum dot

Optical bipolaron properties in the symmetric quantum dot were investigated using the Lee-Low-Pines-Huybrechts method and the Tokuda linear combination operator method. Algebraic expressions are derived for the energies of the fundamental and first excited states, the effective mass, mobility, binding energy and oscillation period of the optical bipolaron. Results prove that the energies of fundamental and first excited states increase with the coupling constant. Another point is that the strong coupling method dominates the weak coupling and the intermediate one when the electron-phonon coupling enhances. We also observe that the binding energy becomes always positive when confinement strength is above 5. In other points, the binding energy of optical bipolaron is well studied in all coupling, especially in weak coupling. It is also noticed that energies are increasing the function of the dielectric ratio and the oscillation period is reducing with the dielectric ratio. This proves that the electron-electron interaction is strengthened in a quantum dot. The stronger the coupling, the higher mobility in the case of low temperature.