Effects of vertex corrections on diagrammatic approximations applied to the study of transport through a quantum dot

LEANDRO TOSI; PABLO ROURA-BAS; ANA MARIA LLOIS; LUIS O. MANUEL

PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS

APS

Lugar: New York; Año: 2011 vol. 83 p. 73301 - 73304

0163-1829

In the present work, we calculate the conductance through a single quantum dot weakly coupled to metallic contacts. We use the spin-1/2 Anderson model to describe the quantum dot, while considering a finite Coulomb repulsion. We solve the interacting system using the noncrossing approximation (NCA) and the one-crossing approximation (OCA). We obtain the linear response conductance as a function of temperature and energy position of the localized level. From the comparison of both approximations we extract the role of the vertexcorrections, which are introduced in the OCA calculations and neglected in the NCA scheme. As a function of the energy position, we observe that the diagrams omitted within the NCA are really important for appropriately describing transport phenomena in Kondo systems as well as in the mixed valence regime. On the other hand, as a function of temperature, the corrections introduced by the OCA partly recover the universal scaling propertiesknown from numerical approaches such as the numerical renormalization group.