Transport through a quantum-dot-ring with one dot connected to two electron reservoirs

Making use of the equation of motion method and Keldysh Green function technique, we obtain a general current formula for a quantum-dot-ring with one of the dots connected to two electron reservoirs under a DC bias voltage. The transmission probability T(ω)T(ω) as a function of electron ωω curve is presented, which displays oscillation structure. The resonant states of the system are found to distribute within an interval centered at ε0ε0 (the dot energy level) with a width of two times the tunnel coupling amplitude between two neighboring dots, the number of the resonant peaks agrees with N (the number of the dots) when inter-dot tunnel coupling is sufficiently large and an odd–even behavior appears at the Fermi energy.