Spatially confined Bloch oscillations in semiconductor superlattices
  In a semiconductor superlattice with long scattering times, damping of Bloch oscillations due to scattering is so small that convective nonlinearities may compensate it and Bloch oscillations persist even in the hydrodynamic regime. In this case, numerical solutions show that there are stable Bloch oscillations confined to a region near the collector with inhomogeneous field, charge, current density and energy density profiles. These Bloch oscillations disappear when damping due to inelastic collisions becomes sufficiently strong. 
L. L. Bonilla, M. \'Alvaro, M. Carretero
cond-mat.mes-hall nlin.PS