Zener Transitions Between Dissipative Bloch Bands

TL;DR

This paper studies how Markoffian dephasing affects electron dynamics in a two-band tight binding model under static electric fields, revealing that dephasing destroys miniband localization and induces Zener resonances.

Contribution

It provides analytical and numerical insights into the impact of dephasing on electron transitions and miniband localization in a two-band system under electric fields.

Findings

Dephasing causes electrons to equally populate both minibands instead of Rabi oscillations.

Miniband localization is destroyed by dephasing.

Decay rate peaks at Zener resonance conditions.

Abstract

Within a two-band tight binding model, we investigate the dynamics of electrons with Markoffian dephasing under the influence of static electric fields. With the help of both numerical and analytic calculations we find that the dephasing ultimately takes electrons which are initially 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 intervention of dephasing. We also obtain the effective decay time for the approach to equal band populations under conditions of small interband communication and in the long-time limit, through a perturbative calculation. The decay rate shows characteristic sharp peaks at values of the parameters which give Zener resonances.