CONDUCTANCE OF A MOTT QUANTUM-WIRE

We consider transport through a one-dimensional conductor subjected to an external periodic potential acid connected to noninteracting leads (a ''Mott quantum wire''). In the case of a strong periodic potential , the conductance is shown to jump from zero, for the chemical potenti al Ising within the Mott-Hubbard gap, to the noninteracting value of 2 e(2)/h, as soon as the chemical potential crosses the gap edge. This b ehavior is strikingly different from that of optical conductivity, whi ch varies continuously with the carrier concentration, In the case of a weak potential, the perturbative correction to the conductance due t o umklapp scattering is absent away from half filling. [S0031-9007(98) 05293-4].