Impurity pinning in transport through 1D Mott–Hubbard and spin gap insulators

A low energy crossover [V.V. Ponomarenko, N. Nagaosa, Phys. Rev. Lett. 81 (1998) 2304] induced by Fermi liquid reservoirs in transport through a 1D Mott–Hubbard insulator of finite length L is examined in the presence of impurity pinning. Under the assumption that the Hubbard gap 2M is large enough: M>TL≡vc/L (vc: charge velocity in the wire) and the impurity backscattering rate Γ1≪TL, the conductance vs. voltage/temperature displays a zero-energy resonance. Transport through a spin gapped 1D system is also described availing of duality between the backscattered current of this system and the direct current of the Mott–Hubbard insulator.