Antiresonance of electron tunneling through a four-quantum-dot ring with two side-coupled quantum dots

Making use of the equation of motion method and Keldysh Green function technique, we obtain the current formula for a two-terminal four-quantum-dot-ring with two side-coupled quantum dots under a DC bias voltage. Antiresonance and resonance of electron tunneling is studied by numerical calculations. Only when the quantum dots in the ring has the same single electron energy level with that of the side-coupled quantum dots, i.e. εi0=ε0 and both side-coupling are turned on at the same time, the antiresonance appear exactly at ε0ε0.