Threshold features in transport through a 1D constriction

Abstract

Suppression of electron current $ ΔI$ through a 1D channel of length $L$ connecting two Fermi liquid reservoirs is studied taking into account the Umklapp electron-electron interaction induced by a periodic potential. This interaction causes Hubbard gaps $E_H$ for $L \to \infty$. In the perturbative regime where $E_H \ll v_c/L$ ($v_c:$ charge velocity), and for small deviations $δn$ of the electron density from its commensurate values $- ΔI/V$ can diverge with some exponent as voltage or temperature $V,T$ decreases above $E_c=max(v_c/L,v_c δn)$, while it goes to zero below $E_c$. This results in a nonmonotonous behavior of the conductance.

Final variant published in PRL, 79, 1714; minor corrections