ZENER TRANSITIONS BETWEEN DISSIPATIVE BLOCH BANDS

Within a two-band tight-binding model, we investigate the dynamics of electrons with Markoffian dephasing under the influence of static elec tric fields. With the help of both numerical and analytic calculations we find that the dephasing ultimately takes electrons that are initia lly located in one miniband to equal population of the two minibands, instead of undergoing persistent Rabi flop, as they do in the absence of scattering. Miniband localization is wholly destroyed by the interv ention of dephasing. We also obtain the effective decay time for the a pproach to equal band populations under conditions of small interband communication and in the long-time limit, through a perturbative calcu lation. The decay rate shows characteristic sharp peaks at values of t he parameters that give Zener resonances. [S0163-1829(98)06116-5].