Quantum noise in ac-driven resonant-tunneling double barrier structures: Photon-assisted tunneling vs. electron anti-bunching

摘要

We study the quantum noise of electronic current in a double barrier systemwith a single resonant level. In the framework of the Landauer formalism wetreat the double barrier as a quantum coherent scattering region that canexchange photons with a coupled electric field, e.g. a laser beam or a periodicac-bias voltage. As a consequence of the manyfold parameters that are involvedin this system, a complicated step-like structure arises in the non-symmetrizedcurrent-current auto correlation spectrum and a peak-like structure in thecross correlation spectrum with and without harmonic ac-driving. We present ananalytic solution for these noise spectral functions by assuming a Breit-Wignerlineshape. In detail we study how the correlation functions are affected byphoto-assisted tunneling (PAT) events and discuss the underlying elementaryevents of charge transfer where we identify a new kind of contribution toshot-noise. This enables us to clarify the influence of a not centeredirradiation of such a structure with light in terms of contributionsoriginating from different sets of coherent scattering channels. Moreover weshow how the noise is influenced by acquiring a scattering phase due to thecomplex reflection amplitudes that are crucial in the Landauer approach.