Study On The Transport Properties Of Double Quantum Dots

In this thesis,we use the hierarchical equations of motion to study the dy-namical properties of series coupled double quantum dot system in several typical tunneling regions,such as sequential tunneling,cotunneling and Kondo regimes.Firstly,we consider the transport properties of the system in the case of sequen-tial tunneling.With the changing of the Coulomb interaction intensity between quantum dots,we find that there are obvious peak or dip signals at the Rabi frequency,and there will be non-Markovian steps near the resonance frequency.Then,we modify the system parameters to study in the cotunneling region.In this region,We change the coupling strength between the quantum dots and the bias voltage added to the double quantum dot system to explore the system's trans-port properties.We found that Rabi signal increases with the coupling strength between the dots,and the increase of the positive Rabi frequency is more obvious than the increase of the negative Rabi frequency;when changing the voltage,with the increase of transport channel,at the resonance frequency noise spectrum in the non-Markovian steps is also increasing.Finally,we reduce the system temper-ature to below the Kondo temperature,and study the dynamic behavior of the series coupled double quantum dots in the Kondo area.By calculating the current noise spectrum,we can better understand the transport properties of series cou-pled double quantum dots under different tunneling regimes,because the current noise spectrum contains more information than the average current.