Kondo effect and singlet-triplet splitting in coupled quantum dots in a magnetic field
Department of Physics and Astronomy, University of
Basel Klingelbergstrasse 82, CH-4056 Basel, Switzerland
Accepted: 17 January 2003
We study the interplay between Kondo correlations and the singlet-triplet exchange splitting K between the two spins in a double quantum dot. We calculate the cotunneling current with elastic and inelastic contributions and its renormalization due to Kondo correlations, away and at the degeneracy point K=0. We show that these Kondo correlations induce pronounced peaks in the conductance G as a function of magnetic field B, inter-dot coupling , and temperature. The long-range part of the Coulomb interaction becomes visible due to Kondo correlations resulting in an additional peak in G vs. with a strong B-field dependence. These conductance peaks thus provide direct experimental access to K, and thus to a crucial control parameter for spin-based qubits and entanglement.
PACS: 73.23.Hk – Coulomb blockade; single-electron tunneling / 72.15.Qm – Scattering mechanisms and Kondo effect / 73.63.-b – Electronic transport in mesoscopic or nanoscale materials and structures
© EDP Sciences, 2003