Landauer-Büttiker formula for time-dependent transport through resonant-tunneling structures : a nonequilibrium Green’s function approach

Abstract

A nonequilibrium Green’s-function formalism is employed to study the time-dependent transport through resonant-tunneling structures. With this formalism, we derive a time-dependent Landauer-Büttiker formula that guarantees current conservation and gauge invariance. Furthermore, we apply the formula to calculate the response behaviors of the resonant-tunneling structures in the presence of rectangular-pulse and harmonic-modulation fields. The results show that the displacement current plays the role of retarding the tunneling current.