Dynamic regime of electron transport in correlated one-dimensional conductor with defect

• Boundary conditions for non-ideal contacts with a quantum wire, which take into account relaxation in the leads, are derived.
• New regime of conduction in which a dc current is supplemented by ac oscillations is predicted in the wire with impurity on a non-ideal contact.
• IV curves and noise spectrum are calculated in the limit of high voltages.
• Both spinless and spinful cases are studied

The electron transport in a 1D conductor with an isolated local defect such as an impurity or a non-adiabatic contact is studied theoretically. A new regime of conduction in correlated 1D systems is predicted beyond the well-known regime of tunneling resulting in the power-law I–V-curves. In this regime a quantum wire becomes “opened” at a voltage bias above the threshold value determined by 2kF-component of impurity potential renormalized by fluctuations, giving rise to a rapid increase of the dc current, I¯, accompanied by ac oscillations of frequency f=I¯/e. Manifestations of the effect resemble the Coulomb blockade and the Josephson effect. The spin bias applied to the system affects the I–V curves due to violation of the spin-charge separation at the defect site. The 1D conductor is described in terms of the Tomonaga–Luttinger Hamiltonian with short range or long-range Coulomb interaction by means of the bosonization technique. We derive boundary conditions that take into account relaxation in the leads and permit to solve non-equilibrium problems. Charge fluctuations are studied by means of Gaussian model which can be justified strictly in the limit of large voltages or strong inter-electronic repulsion. Spin fluctuations are taken into account strictly by means of the refermionization technique applicable in the case of spin-rotation invariant interaction.