We investigate the dynamical interaction between an electron crystal trapped above the surface of liquid helium and surface waves ('ripplons') excited by its motion. At rest, the electron system is 'dressed' by static ripplons to form 'ripplopolaron' states. As the electrons move, resonant ripplon scattering results in a growth of the ripplopolaron effective mass, on timescales comparable with the inverse of the ripplon frequency (similar to 100 ns). Under sufficient driving force, the electron system decouples from the surface waves and moves at high velocity, before decelerating sharply when the electron solid and surface excitations recouple to form a 'new' ripplopolaron system. The mass of the newly formed ripplopolarons is similar to that in the initial static case.
- 2-DIMENSIONAL ELECTRONS
- NONLINEAR CONDUCTIVITY