Advanced Theory of Instability in Tunneling Nanostructures

This work is concerned with the quantum structure of resonant tunneling diodes, which exhibits intrinsic instability that can be exploited for the development of high-speed, high-frequency devices. The article examines in detail the physics underlying the non-liner instability, in both a one-band model and a multiple-band model. The theoretical basis of the description of electronic processes in such structures are described in some detail in terms of nonequilibrium Green's functions. Also presented here is a semi-phenomenological model of the resonant tunneling diode based on nonlinear circuit theory. Recent works and progresses in this and related areas are summarized here as well.