Current-voltage characteristics and magnetic moment of a tunnel-coupled double-wire structure

We analyze electron transport and magnetic response of a semiconductor double-wire system in the case when the two parallel wires are connected to leads in series, with the bias voltage potential drop (and associated electric field) and tunnel coupling in the direction perpendicular to the lengths of parallel wires. Explicit analytical expressions are obtained for the lead-to-lead current and for the average magnetic moment induced by an applied magnetic field. We show that the magnetic response of such a system can be either diamagnetic or paramagnetic depending on the applied bias and the equilibrium chemical potential of the leads.