Theory of the excitonic lineshape in low-dimensional structures with rough interfaces

摘要

A quantum mechanical theory of single-particle motion under the influence of a stochastic potential is presented. By solving the Dyson equation, the one-particle Green's function can be determined approximately. Gaussian distribution, an explicit expression is derived for the spectral function. The analytical results are in good agreement with numerically calculated data. The theory is applied to excitons on rough interfaces. The optical absorption of excitons on rough surfaces can be traced back to the one-particle Green's function for the center-of-mass motion. In contrast to the classical treatment, the asymmetry of the lines and the redshift of the maxima can be explained. The coefficients for linewidth and asymmetry can be expressed in terms of the excitonic wavefunction and the binary correlation function of the stochastic potential.