Influences of a Side-Coupled Triple Quantum Dot on Kondo Transport Through a Quantum Dot

Kondo transport properties through a Kondo-type quantum dot (QD) with a side-coupled triple-QDstructure are systematically investigated by using the non-equilibrium Green’s function method.We firstly derive theformulae of the current, the linear conductance, the transmission coefficient, and the local density of states.Then we carryout the analytical and numerical studies and some universal conductance properties are obtained.It is shown that thenumber of the conductance valleys is intrinsically determined by the side-coupled QDs and at most equal to the numberof the QDs included in the side-coupled structure in the asymmetric limit.In the process of forming the conductancevalleys, the side-coupled QD system plays the dominant role while the couplings between the Kondo-type QD and theside-coupled structure play the subsidiary and indispensable roles.To testify the validity of the universal conductanceproperties, another different kinds of side-coupled triple-QD structures are considered.It should be emphasized thatthese universal properties are applicable in understanding this kind of systems with arbitrary many-QD side structures.