Properties of optical bipolaron in symmetric quantum dot

Abstract

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. • The ground and first excited energies, binding energy, Oscillation Period, Effective mass and mobility of bipolaron. • We have plotted Ground state energy and excited state energy of bipolaron versus the electron-phonon coupling constant in different couplings. • Ground state energy, excited state energy and oscillation period of bipolaron versus confinement strength at various values of the dielectric ratio are plotted. • We plotted Variation of binding energy of bipolaron versus confinement strength in all coupling. (a) Ω ≺ 4 ; (b) Ω ≻ 4 • We have plotted Variation of mobility versus confinement strength at different values of dielectric ratio. • We have plotted Variation of ground state effective mass (a) and excited effective mass (b) versus electron-phonon coupling constant.