The Effect Of Electronic Correlations On Magnetotransport Through A Parallel Double Quantum Dot

Recently, double quantum dot is widely investigated in nanophysics and the transport properties of double quantum dot coupled to ferromagnetic electrodes attract much attention form both from both experimental and theoretical sides. In fact, the double quantum dot is one of the simplest models, referred as artificial molecules, and reflects the behavior of real molecules. The important role played by double quantum dot in quantum computation is particularly interesting and a variety of different phenomena has been showed. Moreover, on the theoretical side, the tunnel magnetoresistance and spin accumulation effects are displayed when the double quantum dot is coupled to ferromagnetic leads. Not like the transport properties through single quantum dot being extensively studied experimentally, the ones in multi-dot system are still in initial stage, and experimental task and theoretical investigation are needed.In this paper we will discuss the relation between the transport properties and the electronic correlation, including spin exchange interaction and Coulomb correlation. To obtain the transport characteristics in different regimes as we set, we use the generalized master equation method for the reduced density operator of the double quantum dot. Then we calculate the current, conductance and tunnel magnetoresistance for double quantum dot system with various electronic correlation conditions. Comparing with the transport properties in the system without electronic correlation, we find a high peak and a negative part of tunnel magnetoresistance, meanwhile, a negative differential conductance is found in some transport regimes. Furthermore, using the schema of reduced density, we analyze the dependence of transport characteristics on the electronic correlation.