Abstract
We investigate theoretically linear and nonlinear quantum transport through a smallerquantum dot in a Kondo regime connected to two leads in the presence of a largerside-coupled noninteracting quantum dot, without tunneling coupling to the leads. To dothis we employ the slave boson mean field theory with the help of the KeldyshGreen’s function at zero temperature. The numerical results show that the Kondoconductance peak may develop multiple resonance peaks and multiple zero points in theconductance spectrum owing to constructive and destructive quantum interferenceeffects when the energy levels of the large side-coupled noninteracting dot arelocated in the vicinity of the Fermi level in the leads. As the coupling strengthbetween two quantum dots increases, the tunneling current through the quantumdevice as a function of gate voltage applied across the two leads is suppressed.The spin-dependent transport properties of two parallel coupled quantum dotsconnected to two ferromagnetic leads are also investigated. The numerical results showthat, for the parallel configuration, the spin current or linear spin differentialconductance are enhanced when the polarization strength in the two leads is increased.
Published Version
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