The effect of the interdot Coulomb interaction on Kondo resonances in series-coupled double quantum dots

• Published in: Physica. B, Condensed matter Condensed matter, 2011-02, Vol.406 (4), p.749-755
• Main Authors: Wu, Shao-quan, Chen, Jia-feng, Zhao, Guo-ping
• Format: Article
• Language: English
• Subjects: Approximation; Condensed matter; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Coulomb friction; Density of states; Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport in multilayers, nanoscale materials and structures; Exact sciences and technology; Interdot Coulomb interaction; Kondo resonances; Kondo temperature; Mathematical analysis; Occupation; Physical properties; Physics; Quantum dots; Slave-boson mean-field
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2010.11.057

We theoretically investigate the effect of the interdot Coulomb repulsion on Kondo resonances in the series-coupled double quantum dot coupled to two ferromagnetic leads. The Hamiltonian of our system is solved by means of the slave-boson mean-field approximation, and the variation of the density of states, the transmission probability, the occupation number, and the Kondo temperature with the interdot Coulomb repulsion are discussed in the Kondo regime. The density of states is calculated for various interdot Coulomb repulsions with both parallel and antiparallel lead-polarization alignments. Our results reveal that the interdot Coulomb repulsion greatly influences the physical property of this system, and relevant underlying physics of this system is discussed. ► When the interdot Coulomb repulsion is ignored, our results are consistent with other works. ► When U≠0, the Kondo resonance is compressed in the equilibrium case, but is enhanced in the non-equilibrium case. ► The interdot Coulomb repulsion is one of the important parameters that controls transport phenomena. ► The rich physical behaviour of DQD systems can be attributed to the interdot Coulomb repulsion.