Theory of guided electron waves in symmetric coupled-quantum-well waveguides

Based on multimode coupling theory, a rigorous theory of guided electron waves in symmetric coupled-quantum-well waveguides is proposed in this paper. The main conclusions of the theory are the following: The normal modes in symmetric coupled-quantum-well waveguides can only be produced by the states in the two uncoupled-quantum-well channels for which the level difference is small; for a certain symmetric coupled-quantum-well waveguide structure, the electron with a different energy has a different transfer length under certain external conditions; the transfer length, the coupling constant, and the propagation constant can be calculated exactly by the theory for the electrons with different energies in the symmetric coupled-quantum-well waveguide. A mesocopic device, the electron energy filter, is proposed.