Decoherence effects due to exciton-phonon interaction in CdSe quantum dots: Contribution of the piezoelectricity and deformation potential couplings

摘要

We analyse decoherence effects of an exciton in II-VI semiconductor quantum dot. We calculate the scattering rate of excitons by acoustic phonons laying a foundation for work on understanding carrier relaxation in quantum dots providing then a basis for studying decoherence phenomena in these systems. We considered two exciton-acoustic phonons scattering mechanisms the standard deformation potential coupling and the piezoelectric coupling. The latter was found to be relatively important in large dots. We discuss the influence of an external applied magnetic field and the dot size on the scattering rate. We show that it depends strongly on the quantum dot size, then using a modulated external magnetic field the interaction of the exciton and acoustic phonon modes can be modified in a wide range.