ABSTRACT

Since the invention of the superlattice by Esaki and Tsu [ 1] thirty years ago, many fundamental properties of a periodic potential predicted by the early works of quantum mechanics could be explored experimentally. The main reason for the great success of superlattices is their usability for tailored artificial structures which are not provided by nature and thus giving access to new experimental regimes. One of these experiments of general interest was the observation of Bloch oscillations (BO) [2,3]. The application of a static electric field to an electron in a periodic potential leads to an oscillatory motion of this electron in time and space which is an amazing example of nonlinear transport. Since the mean scattering time is usually below the oscillation period, which scales with the width of the transport band, BO have not yet been observed in natural crystals, and only the advent of tailored superlattices with their much narrower minibands and larger lattice period has made these experiments possible.