Nonlinear transport of Wigner crystal on liquid helium in microchannel devices

Electrons trapped on the surface of liquid helium present the cleanest Coulomb system that can be found in nature. The ground state of the system is a classical 2D Wigner crystal, which is realized already at moderately low temperatures around 1K and without magnetic field. The surface of liquid helium substrate is free from disorder. On the other hand, the Wigner crystal can strongly interact with the quantized field of capillary waves on the helium surface, ripplons. This provides a unique opportunity to study the coupled dynamics of a charged system and medium excitations in a disorder-free environment.

It was demonstrated that confining electrons in capillary-condensed microchannel devices provides important advatages for studying such dynamics via the transport measurements [1]. In particular, the time-resolved transport measurements revealed an interesting stick-slip dynamics and provided an insight into dynamic phases of the driven system [2]. A novel regime of ripplo-polaronic charge transport of Wigner crystal was demonstrated in a three-terminal microchannel device [3]. Finally, such studies could be interesting in the general context of friction whose microscopic mechanism presents a challenging question.