Suppresion of Bloch oscillations by weak disorder in semiconductor   superlattices
  We investigate the dephasing dynamics of Bloch oscillations in semiconductor superlattices by means of a very simple model including disorder and applied electric fields. A thorough numerical study of our model allows us to claim that small, unintentional well width fluctuations can be responsible for fast dephasing of Bloch oscillations at low temperatures. We show that the lifetime of Bloch oscillations is controlled by a characteristic time which depends on the degree of disorder and is independent of the electric field. This result is further supported by the excellent agreement between our model calculations and several recent experiments, and leads to specific new predictions. 
Enrique Diez, Francisco Dominguez-Adame, and Angel Sanchez