Resonant coupling between symmetric and asymmetric Stark Ladders in a double period superlattice

We have investigated resonant coupling between coupled Stark ladder states in a double-period GaAs/AlAs superlattice with a fixed well width (Lz = 3.2 nm) and alternating thinner (LB = 0.45 nm) and thicker (LB = 0.9 nm) barriers. Under applied electric field, the Stark ladder states coupled by the thinner barrier reveal a hierarchy of anticrossings in optical transitions due to resonances between the lower symmetric and the higher antisymmetric states belonging to the different well-pairs. By virtue of symmetry properties of the Stark ladder eigenstates, these resonances are rigorously identified by calculating the evolution of the eigenenergies and the wavefunctions using the transfer matrix method.