Strong electron-phonon coupling regime in self-assembled quantum dots

摘要

We report on the magneto-optical evidence and theoretical modelling of polaron effects in selfassembled InAs/GaAs quantum dots. Using far-infrared magneto-transmission experiments performed up to 28 T at T = 2 K in doped QDs samples, we investigate the electronic transitions between the ground and first excited states. We observe very large anticrossings in the B-dispersion of the magneto-optical transitions, whose existence can not be explained by a purely electronic model. We thus calculate the coupling between the mixed electron-lattice states using the Froehlich hamiltonian and determine the polaron states and the energies of the dipolar electric transitions. An excellent agreement between the calculations and the experimental data is obtained, demonstrating that the magneto-optical transitions occur between polaron states. We predict that the strong coupling regime exists also in GaN/AlN quantum dots.