Investigation On The Transport Properties Of A Double Quantum Dots System With Coulomb Correlation

The electron transport properties in low-dimensional mesoscopic systems havebeen investigated extensively. The application of quantum mechanics in condensedmatter physics is promoted by the exploration for the phenomenon and the basic law ofthe mesoscopic systems, and the quantum dots system is an important part to researchmesoscopic systems. On one hand, the quantum dots systems possess plentiful physicalqualities, and their transport properties can be controlled by adjusting the relevantparameters of the systems. For instance, the inter-dot or intra-dot Coulomb correlation,the inter-dot coupled interaction, and temperature have important effects on theconductance of a correlated quantum dots system. On the other hand, many orientationsof the coupled quantum dots such as string type, paratactic type and T-type, make thevariousness in researches.In this paper, the coupled quantum dots system is studied based on the FermiGreen’s function method. the analytical algebraic expressions of the DC current,occupation, spin accumulation and differential conductance are obtained, under thecondition that the Coulomb interaction between the electrons in the quantum dots istaken into account. Meanwhile, the impact of various parameters on the electronictransport properties and the variation trend are discussed. This paper includes thefollowing content:(1) By solving the self-consistent, the variation trends of occupation of oppositespinning in the same quantum dots with Coulomb interaction, bias, resonance width andtemperature are obtained. At the same time,it is found that there will be magnetismwhen the occupation of opposite spinning are not equal. The investigate shows that theCoulomb interaction in the quantum dots and low temperature are necessary conditionfor the appear of magnetism, only when magnetic bias is between the energy levels0and0U. Through analysis of DC current and differential conductance curves, thepresentation of DC current and conductance before and after the emergence ofmagnetism. The result shows that the emergence of magnetism make the DC currentcurve of quantum dots have stepped profile and change differential conductance curve from a single peak to the previous bimodal.(2) The results show that the truncation approximation has little influence on theelectron transport system of coupled quantum dots with Coulomb associated. So, itmakes computation more convenient and the value of each parameter more accurate,while taking the low-level Green’s function truncation approximation into consideration.