Resonant coupling between Stark-ladder states in GaAs/AlGaAs superlattice

We carried out electroreflectance measurements in a GaAs/AlGaAs superlattice at 77K in order to investigate the resonant couplings between the Stark-ladder states. The experimental data are analyzed by using tight-binding theory, including the electric field effect. From the comparison between the theoretical calculations and experimental results, the resonant couplings are found to occur between Stark-ladder states of the heavy-hole minibands. The observed transition energies of the resonant couplings do not cross each other, and the tight-binding calculations also indicate that the splittings of the energy levels are induced by the resonant couplings. PACS: 7865, 7820J.