RESONANT-TUNNELING THROUGH COUPLED DOUBLE-QUANTUM-WELL

A double-well resonant tunneling structure has been investigated caref ully using the nonequilibrium Green's function method. We find that in the transmission probability two maxima appear even when the two leve ls have the same energy. This characteristic is attributed to the reso nant tunneling through mixed quasibound states. The tunneling current formula through this system under a de voltage has been derived exactl y. Three different cases are considered and several novel properties a re found, which manifest coherent characteristics of the tunneling pro cess.