Irreducible Green Functions Method Applied to Nanoscopic Systems |

G. Górski
Faculty of Mathematics and Natural Sciences, University of Rzeszów, S. Pigonia 1, 35-959 Rzeszów, Poland |

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The equation of motion method for the Green functions is one of the tools used in the analysis of quantum dot system coupled with the metallic and superconducting leads. We investigate modified equation of motion, based on differentiation of double-time temperature dependent Green functions both over the primary time t and secondary time t'. Our equation of motion approach allows us to obtain the Abrikosov-Suhl resonance in the particle-hole symmetric case and also in the asymmetric cases. We will apply the irreducible Green functions technique to analyses of the equation of motion applied to the dot system. This method gives a workable decoupling scheme breaking the infinite set of the Green function equations. We apply this technique to calculate the density of the states and the differential conductance of single-level quantum dot with the Coulomb repulsion attached to one metallic and one superconducting leads (N-QD-SC). Our results are compared with the previous calculations. |

DOI: 10.12693/APhysPolA.130.551 PACS numbers: 73.63.Kv, 73.23.Hk, 74.45.+c |