Fano Effect and Anti-Resonance Band in a Parallel-Coupled Double Quantum Dot System with Two Multi-Quantum Dot Chains**Supported by the National Natural Science Foundation of China under Grant Nos 11447132 and 11504042, the Chongqing Science and Technology Commission Project under Grant Nos cstc2014jcyjA00032 and cstc2016jcyjA1158, and the Scientific Research Project for Advanced Talents of Yangtze Normal University under Grant No 2017KYQD09.

Abstract

A parallel-coupled double quantum dot (PCDQD) system with two multi-quantum dot chains is designed. Conductance versus Fermi energy level is investigated utilizing the non-equilibrium Green’s function approach. If two quantum dots are added on each side of the PCDQD system, additional Breit–Wigner and Fano resonances occur in the conductance spectra. If quantum dots are added on one side of the system, small Fano resonances can be observed in the conductance spectra. Adjusting the number of side-coupled quantum dots, the anti-resonance bands emerge at different positions, which makes the system applicable as a quantum switching device. Moreover, the I–V characteristic curve presents the step characteristic and the width of the step decreases with increasing the number of side-coupled quantum dots.