Eur. Phys. J. B 53, 109-120 (2006)
https://doi.org/10.1140/epjb/e2006-00352-1

Conductance of nano-systems with interactions coupled via conduction electrons: effect of indirect exchange interactions

¹ 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

Received: 31 May 2006
Revised: 22 August 2006
Published online: 22 September 2006

Abstract

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 k_F in an infinite chain embedding two scatterers separated by a segment of length L_c. The fermions interact only inside the two scatterers. The dependence of one scatterer onto the other exhibits oscillations of period π/k_F which decay as 1/L_c and which are suppressed when L_c exceeds the thermal length L_T. The analytical results given by the Hartree-Fock approximation are compared with exact numerical results obtained with the embedding method and the DMRG algorithm.