Interplay of exciton or electron transfer and relaxation

Abstract

A trick permitting to apply generalized master equation (GME) theory together with canonical transformation but quantities of interest (single-particle density matrix) remaining untransformed is applied to the time-convolutionless GME approach for carriers interacting with phonons by a local linear coupling. In contrast with time convolution theories (Mori, time-convolution GME), it is found that the second-order perturbational approach in the above coupling is already able to yield a loss of coherence of carrier propagation with increasing time as well as a proper asymptotic state at any temperature. Moreover, dependence on the degree of the initial polaron cloud formation is shown, as expected but again in contrast with the above theories, to disappear explicitly after a short period of the polaron cloud reconstruction from equations determining the time development of the single-particle density matrix. A prediction on the Weber effect and charge-carrier generation process in narrow band materials is given. Correspondence with a recent generalization of the Haken-Strobl-Reineker model is found.