Enhanced current fluctuation in Coulomb blockade regime of multilevel quantum dot

33rd International Conference on the Physics of Semiconductors

Iwasaki, Atsushi^1 ; Eto, Mikio^1

Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama

223-8522, Japan^1

关键词: Analytical expressions;    Coulomb-blockade regime;    Current fluctuations;    Ground level;    Inelastic cotunneling;    Non equilibrium;    Poisson noise;    Tunneling process;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/864/1/012034/pdf
DOI  :  10.1088/1742-6596/864/1/012034

来源: IOP

【 摘 要 】

Nonequilibrium current fluctuation is theoretically studied through a multilevel quantum dot in the Coulomb blockade regime, where the higher-order tunneling processes, "cotunneling," are dominant in the transport. The current fluctuation shows a Poisson (super-Poisson) noise in the elastic (inelastic) cotunneling regime when the bias voltage eV between the leads is smaller (larger) than the excitation energy Δ from the ground level in the quantum dot. The super-Poisson noise is remarkably enhanced by the degeneracy of the excited states around the beginning of inelastic cotunneling at eV ≈ Δ, qualitatively in good agreement with a recent experimental result. An analytical expression is given for the current fluctuation as a function of degeneracy.