Influence of temperature and LO phonon effects on the effective mass of quasi 0D bipolarons in the strong-coupling limit

In this paper, based on the of Huybrechts strong-coupling polaron model, the Tokuda modified linear-combination operator method, the Lee–Low–Pines variational method and the quantum statistics theory were used to study the temperature dependence of the effective mass of quasi-zero-dimensional strong-coupling bipolarons. The expressions for the effective mass and the mean number of longitudinal optical (LO) phonons of the strong-coupling bipolaron were derived. Numerical results show that the effective mass and the mean number of LO phonons of the bipolaron all decrease with increasing the relative distance between two electrons or the radius of the quantum dot, but they increase with increasing the electron–phonon coupling strength; the effective mass of the bipolaron decreases with the increase of the temperature; the variation of the mean number of LO phonons of the bipolaron with the temperature presents the opposite trend because of the high and low temperature difference.

► Studying the effective mass of quasi-zero-dimensional strong-coupling bipolarons.
► The expression for the effective mass of the strong-coupling bipolaron is derived.
► The variation of the effective mass of bipolarons with the parameters is discussed.
► The expression for the mean number of LO phonons of the bipolaron is obtained.
► Researching the relation of the mean number of LO phonons with the parameters.