Bistability of a Driven Wigner Solid on the Surface of Liquid Helium
David G. Rees1,2, Sheng-Shiuan Yeh1, Ban-Chen Lee1*, Juhn-Jong Lin1,2,3, Kimitoshi Kono1,2
1Institute of Physics, National Chiao Tung University, Hsinchu, Taiwan
2Center for Emergent Matter Science, RIKEN, Wako, Japan
3Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan
* presenting author:Ban-Chen Lee,
We investigate the decoupling of an electronic crystal (Wigner solid, WS) from ripplonic polarons (or ‘dimple lattice’, DL) formed at the surface of liquid helium. The WS is confined in a microchannel several microns wide. We use an arrangement of gate electrodes to tune the electron density and the strength of electrostatic confinement in the microchannel. This allows us to control the number of electron rows in the quasi-1D electron lattice, from 1 to several tens. The decoupling of the WS from the liquid helium substrate can be induced by the application of a sufficiently strong driving electric field parallel to the helium surface, along the microchannel. However, we find that under repeated voltage ramps the threshold decoupling force is not a constant but exhibits a Gaussian-like distribution. When subjected to continuous sinusoidal driving the electron system can become ‘locked’ in distinct transport modes in which decoupling does or does not occur during each ac cycle. We demonstrate that when the probability of a decoupling event occurring during each ac cycle is small but finite the stochastic nature of the WS sliding gives rise to spontaneous telegraph-like switching between the transport modes. The switching rate between the two transport modes is exponentially sensitive to the WS transport properties.

Keywords: surface-state electrons, Wigner crystal, stick-slip friction, Bistability, liquid helium