The role of phase coherence length in electron transport through a Kondo double quantum dot interferometer with Rashba interaction

Abstract

A system composed of Aharonov–Bohm ring with two quantum dots in its arms is considered theoretically. One of the dots is in Kondo regime, whereas the other one is effectively noninteracting. Additionally, Rashba interaction inside the dots can produce spin polarization of the current through the device. This configuration is mapped on the system of a correlated impurity embedded in a host with energy, flux, and spin‐dependent density of states. It is shown that the phase coherence length as compared to the circumference of the ring has crucial influence on the conductance and its spin polarization. When both the lengths are comparable the appearance of dark states becomes possible. Also spin polarization of conductance arises with maximal value for gate voltage where strongly correlated dot enters Kondo regime. In contrast, in the limit of phase coherence length shorter than circumference of the device the spin polarization of conductance totally vanishes.