Binding energy of biexcitons in a quantum disk

摘要

The method of few-body physics is applied to treat a system of two excitons in a quantum disk. The binding energy of a biexciton is calculated for various confinements. It is found that the biexciton binding energy drops sharply to zero, i.e. there exists a critical radius R-C, such that if R > R-C (R < R-C), the biexciton configuration is stable (unstable). From E-b(xx) = 0, we obtain R-C similar to 05a(B)*, indicating the existence of a repulsive core of interaction between the two neutral excitons. The dependence of the ratio of biexciton binding energy to that of the exciton on the disk thickness is also investigated. [References: 29]