Rabi oscillations between dissipative Bloch bands

Within a two-band tight-binding model driven by DC-AC electric fields, we i nvestigate the dynamics of electrons with Markoffian dephasing. We find tha t Rabi oscillations between the Bloch bands under the resonant condition ma y be destroyed by scattering from lattice imperfections. Through a perturba tive calculation, we also obtain the effective decay time for the approach to equal Bloch band populations under conditions of small interband couplin g and in the long-time limit. The decay rate shows characteristic sharp pea ks at values of the parameters that give a signature of Rabi oscillations, and quasienergy spectra display avoided crossings at the same time. (C) 200 1 Elsevier Science B.V. All rights reserved.