Conductance oscillations of a quantum wire disturbed by an adatom

The conductance through a quantum wire with a side-attached atom (adatom) is investigated using the tight-binding Hamiltonian and Green function method. The adatom can be coupled with one or more atoms and it disturbs the electron transport through the wire. Analytical formulae for the transmittance are obtained for the most probable connections. Also, conductance oscillations as a function of the wire length are studied for a disturbed wire. It is shown that the period of these oscillations remains unchanged in the presence of the adatom but the value of the conductance strongly depends on the adatom-wire couplings and the kind of connections of the adatom to the wire