Eur. Phys. J. B (2016) 89: 255
https://doi.org/10.1140/epjb/e2016-70215-3

Regular Article

Dynamic shot noise in a quantum dot coupled with Majorana fermions under the perturbation of microwave fields

¹ School of Physics, Beijing Institute of Technology, Beijing 100081, P.R. China
² Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, P.R. China

^a e-mail: zhaohonk@bit.edu.cn

Received: 9 April 2016
Received in final form: 25 August 2016
Published online: 24 November 2016

Abstract

The dynamic properties of a quantum dot (QD) coupled with Majorana fermions under the perturbation of microwave fields (MWFs) have been investigated through the nonequilibrium Green’s function (NGF) technique. The photon-assisted differential conductance, current, shot noise, and Fano factor have been evaluated in the Nambu representation. The normal electron tunneling and Andreev reflections contribute to the transport effectively, and novel conductance peaks appear around each photon-induced side channel. The shot noise is enhanced by increasing the interaction strength of Majorana fermions evidently, while it is suppressed accompanying with peak-valley structures by the MWFs. For the symmetric transmission where the QD energy E_d = 0, terminal current disappears when the source-drain bias eV is removed. For the asymmetric transmission where E_d ≠ 0, there exists nonzero pumping current induced by the applied MWF. The saturate pumping current increases with increasing E_d as eV = 0 and E_d ≠ 0, but the shot noise increases with decreasing E_d. As the coupling energy between the Majorana fermions becomes zero, the Fano factor reaches the robust value F ≈ 0.38 as eV → 0.