Abstract
The Kondo effect in coupled quantum dots is investigated theoretically under magnetic fields. We show that the magnetoconductance (MC) illustrates the peak structures of Kondo resonant spectra. When the dot-dot tunneling coupling is smaller than the dot-lead coupling Δ (level broadening), Kondo resonant levels appear at the Fermi level The Zeeman splitting of the levels weakens the Kondo effect, which results in a negative MC. When is larger than the Kondo resonances form bonding and antibonding levels, located below and above respectively. We observe a positive MC since the Zeeman splitting increases the overlap between the levels at In the presence of antiferromagnetic spin coupling between the dots, the sign of the MC can change as a function of the gate voltage.
- Received 22 March 2001
DOI:https://doi.org/10.1103/PhysRevB.64.073307
©2001 American Physical Society