Elastic and Inelastic Resonant Tunneling in an Imperfect Superlattice

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Resonant tunneling through a double barrier is a well established phenomenon. Here we consider transport in a superlattice with a disruption, and inelastic effects therein. The disruption separates the superlattice into two perfect sections, described by a miniband, and leads to a resonant tunneling within the miniband. The superlattice is placed in the base of a transistor with a ballistic launcher in a structure similar to the ones proposed by Capasso and Kiehl (1985). The experimental situation we envisage is shown in Fig. 1. The disruption may be caused by either some uncontrollable agent, or by intentionally modifying the growth conditions. Gelfand et al. (1989) have recently developed a theoretical framework for inelastic tunneling through a single barrier within a tight-binding model, where the energy-momentum relation is E(p) = -2t cos(pa). We suggest that this model has direct physical relevance to transport in a miniband formed in a superlattice (choosing the parameters appropriately). The effect of the disruption (see Fig.1) can be modeled by an extra potential barrier term in the Hamiltonian.