Transfer Matrix Method to Compute Energy Levels of Superlattices

Using the transfer matrix method the Kronig‐Penney model is generalized to superlattices formed by whatever successions of layers. Imposing the boundary conditions, the miniband structure as well as the envelope wave functions are obtained. As examples, the “enlarged well in a superlattice” problem and the Fibonacci superlattices are discussed. The Lyapunov coefficients as a function of energy are calculated to determine the localization properties of the eigenstates in the entire superlattice spectrum. The single channel Landauer formula is used to get the conductance spectrum. Results are presented for random disordered superlattices.