Electron localization and Bloch oscillations in quantum-dot superlattices under a constant electric field

It is demonstrated that the electron spectrum in ideal two-dimensional and three-dimensional quantum-dot superlattices (SLs) under a constant electric field can be either discrete or continuous depending on the field orientation with respect to the SL crystallographic axes. In the latter case, the width of the resulting transverse miniband depends exponentially on the crystallographic index corresponding to the direction of the field. The electron localization area undergoes dramatic variations with the field orientation in the vicinity of the directions corresponding to the continuous energy spectrum. The Bloch oscillations in this kind of SL are considered. It is established that the scattering of oscillating electrons can be strongly suppressed by an appropriate choice of the field strength and direction. (C) 2001 MAIK "Nauka/Interperiodica".