We analyze the phase transitions of an interacting electronic system weakly coupled to free-electron leads by considering its zero-bias conductance. This is expressed in terms of two effective impurity models for the cases with and without spin degeneracy. We demonstrate using the half-filled ionic Hubbard ring that the weight of the first conductance peak as a function of external flux or of the difference in gate voltages between even and odd sites allows one to identify the topological charge transition between a correlated insulator and a band insulator.
@article{arxiv.cond-mat/0406355,
title = {Detection of topological transitions by transport through molecules and nanodevices},
author = {A. A. Aligia and K. Hallberg and B. Normand and A. P. Kampf},
journal= {arXiv preprint arXiv:cond-mat/0406355},
year = {2009}
}