Electrical conduction and magnetic moment of a biased double-wire system

We analyze electron transport and magnetic response of a semiconductor double-wire system in the case when the wires are connected to leads in series, with tunnel coupling between them. Explicit analytical expressions for the lead-to-lead current and the average magnetic moment induced by an applied magnetic field are obtained. We show that at low temperature 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.