2001/12/31 by Bing Dong, X. L. Lei · 2 citations
Physics and Astronomy · #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Semiconductor Quantum Structures and Devices #cond-mat.mes-hall #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.65.241304
5 pages, 5 figures. Physics Review B (Rapid Communication) (in press)
arxiv created 2002/05/14 · openalex publication_date 2002/05/29 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We propose to study the transport through tunneling-coupled double quantum dots (DQD's) connected in series to leads, using the finite-U slave-boson mean-field approach developed initially by Kotliar and Ruckenstein [Phys. Rev. Lett. 57, 1362 (1986)]. This approach treats the dot-lead coupling and the interdot tunneling t nonperturbatively at an arbitrary Coulomb correlation U, and thus allows the antiferromagnetic exchange coupling parameter J=4t2/U to appear naturally. We find that, with increasing interdot hopping, the DQD's manifest three distinct physical scenarios: a Kondo singlet state of each dot with its adjacent lead, a spin singlet state consisting of local spins on each dot, and a doubly occupied bonding orbital of the coupled dots. The three states exhibit remarkably distinct behaviors in transmission spectrum, linear and differential conductances and their magnetic-field dependence. Theoretical predictions agree with numerical renormalization group and Lanczos calculations, and some of them have been observed in recent experiments.