Transport properties of multiple quantum dots arranged in parallel: Results from the Bethe ansatz

Abstract

In this paper we analyse transport through a double dot system connected to two external leads. Imagining each dot possessing a single active level, we model the system through a generalization of the Anderson model. We argue that this model is exactly solvable when certain constraints are placed upon the dot Coulomb charging energy, the dot-lead hybridization, and the value of the applied gate voltage. Using this exact solvability, we access the zero temperature linear response conductance both in and out of the presence of a Zeeman field. We are also able to study the finite temperature linear response conductance. We focus on universal behaviour and identify three primary features in the transport of the dots: (i) a so-called Ruderman-Kittel-Kasuya-Yosida (RKKY) Kondo effect; (ii) a standard Kondo effect; and (iii) interference phenomena leading to sharp variations in the conductance including conductance zeros. We are able to use the exact solvability of the dot model to characterize these phenomena quantitatively. While here we primarily consider a double dot system, the approach adopted applies equally well to N-dot systems. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.