We derive, with the Keldysh non-equilibrium Green function technique, an expression for the fully nonlinear, time-dependent current through an interacting mesoscopic system. For proportionate coupling to the leads, the time-averaged current is simply the integral between the chemical potentials of the time-averaged density of states, weighted by the coupling to the leads, in close analogy to the time-independent result of Meir and Wingreen (1992 Phys. Rev. Lett. 68, 2512). Explicit results for the exactly solvable non-interacting resonant tunnelling system are presented. Due to the coherence between the leads and the resonant site, the current shows a non-adiabatic behaviour with a ringing period which depends on the amplitude of the AC driving voltage. Finally, we establish a connection to recent linear response calculations.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry