Critical conductance of a one-dimensional doped Mott insulator
M. Garst, D. S. Novikov, Ady Stern, and L. I. Glazman

We consider the two-terminal conductance of a one-dimensional Mott insulator undergoing the commensurate-incommensurate quantum phase transition to a conducting state. We treat the leads as Luttinger liquids. At a specific value of compressibility of the leads, corresponding to the Luther-Emery point, the conductance can be described in terms of the free propagation of non-interacting fermions with charge $e/\sqrt{2}$. At that point, the temperature dependence of the conductance across the quantum phase transition is described by a Fermi function. The deviation from the Luther-Emery point in the leads changes the temperature dependence qualitatively. In the metallic state, the low-temperature conductance is determined by the properties of the leads, and is described by the conventional Luttinger liquid theory. In the insulating state, conductance occurs via activation of $e/\sqrt{2}$ charges, and is independent of the Luttinger liquid compressibility.

© 2008 The American Physical Society.