Ivan A. Pshenichnyuk

Despite its simplicity, the model is very important from theoretical point of view. It’s analytically solvable in both scattering and ME approaches and provides a basis for discussion and comparison. The atom of impurity plays a role of the molecular bridge, which contains one electronic level with energy , available for tunneling, and no internal degrees of freedom. Changing the notation of the basis vector to , bridge’s Hamiltonian reads

Leads, as always in this work, are presented by two half-infinite tight binding chains (HITBC). Their Hamiltonian in k-representation reads

where is used to distinguish left and right lead. Chemical potential is in general different for different leads. When we speak about a voltage U, applied to the junction, we assume and .