AC shot noise through a vibrating quantum dot
College of Applied Sciences, Beijing University of Technology, 100124, Beijing, P.R. China
Revised: 26 June 2009
Published online: 31 October 2009
In this paper we investigate the joint effects of the electron-phonon interaction and an external alternating (ac) gate voltage on the spectral density of shot noise through a vibrating quantum dot system, by applying the Lang-Firsov canonical transformation and the Keldysh nonequilibrium Green's function (NGF) technique. We find that the effects of the electron-phonon and electron-photon interaction on the differential shot noise are different. The main resonant peak of the differential shot noise is decreased only when a time-dependent gate voltage is imposed on quantum dot. With the ac field amplitude increasing, the main resonant peak of the differential shot noise decreases. The Fano factor of the system, which exhibits the deviation of shot noise from the Schottky formula, is also studied. Super-Poissonian shot noise appears due to the photon absorption (emission) processes in the low bias voltage region.
PACS: 85.35.-p – Nanoelectronic devices / 73.23.-b – Electronic transport in mesoscopic systems / 72.10.Bg – General formulation of transport theory / 73.21.La – Quantum dots
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2009