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

TL;DR

This paper investigates how electron interactions in nano-systems influence conductance through indirect exchange interactions, revealing oscillatory behavior and decay with distance, using theoretical and numerical methods.

Contribution

It introduces a theoretical model for conductance in interacting nano-systems considering indirect exchange effects, and compares Hartree-Fock results with numerical simulations.

Findings

Oscillations in conductance decay as 1/Lc

Oscillations are suppressed beyond thermal length L_T

Hartree-Fock results agree with numerical methods

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 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 which decay as 1/L\_c and which are suppressed when L\_c exceeds the thermal length L\_T. The Hartree-Fock results are compared with exact numerical results obtained with the embedding method and the DMRG algorithm.