The influence of the external time-dependent field on electron transport through a quantum wire is studied using the model Hamiltonian and evolution operator method. The conductance, transmission coefficient, and current flowing through the wire connected to leads are obtained. It is shown that the average current can be expressed by the corresponding matrix elements of the evolution operator and it satisfies the Landauer-like formula. The sideband peaks in the average current and transmittance are investigated. In contrast to the even-odd conductance oscillation the six-atom period was found in the case where ac external field is applied to the wire.

• Received 26 September 2003

DOI:https://doi.org/10.1103/PhysRevB.69.153303