THRESHOLD FEATURES IN TRANSPORT THROUGH A 1D CONSTRICTION

Suppression of electron current Delta I through a 1D channel of length L connecting two Fermi liquid reservoirs is studied taking into accou nt the umklapp electron-electron interaction induced by a periodic pot ential. This interaction causes Hubbard gaps E-H for L --> infinity. I n the perturbative regime where E-H much less than v(c)/L (v(c) is the charge velocity), and for small deviations delta n of the electron de nsity from its commensurate values, -Delta/V can diverge with some exp onent as voltage Vor temperature T decreases above E-c = max(v(c)/L, v (c) delta n), while it goes to zero below E-c. This results in a nonmo notonic behavior of the conductance.