Conductance of nano-systems with interactions coupled via conduction electrons: effect of indirect exchange interactions
Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Tokyo, 152-8551, Japan
2 Service de Physique de l'État Condensé (CNRS URA 2464), DSM/DRECAM/SPEC, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
Revised: 22 August 2006
Published online: 22 September 2006
A nano-system in which electrons interact and in contact with Fermi leads gives rise to an effective one-body scattering which depends on the presence of other scatterers in the attached leads. This non local effect is a pure many-body effect that one neglects when one takes non interacting models for describing quantum transport. This enhances the non-local character of the quantum conductance by exchange interactions of a type similar to the RKKY-interaction between local magnetic moments. A theoretical study of this effect is given assuming the Hartree-Fock approximation for spinless fermions of Fermi momentum kF in an infinite chain embedding two scatterers separated by a segment of length Lc. The fermions interact only inside the two scatterers. The dependence of one scatterer onto the other exhibits oscillations of period π/kF which decay as 1/Lc and which are suppressed when Lc exceeds the thermal length LT. The analytical results given by the Hartree-Fock approximation are compared with exact numerical results obtained with the embedding method and the DMRG algorithm.
PACS: 71.27.+a – Strongly correlated electron systems; heavy fermions / 72.10.-d – Theory of electronic transport; scattering mechanisms / 73.23.-b – Electronic transport in mesoscopic systems
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2006