Browsing by Author "Lee, Ban-Chen"

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Bistable transport properties of a quasi-one-dimensional Wigner solid on liquid helium under continuous driving
(2017-11-27)
Rees, David G.
;
Yeh, Sheng-Shiuan
;
Lee, Ban-Chen
;
Kono, Kimitoshi
;
Lin, Juhn-Jong
We investigate low-frequency fluctuations in the transport characteristics of a quasi-1D Wigner solid (WS) moving along a liquid helium substrate in response to a sinusoidal driving voltage. The fluctuations occur between distinct transport modes in which the decoupling of the WS from ripplonic polarons (or "dimple lattice," DL) formed on the helium surface does, or does not, occur during each ac cycle. We demonstrate that a Gaussian-like distribution in the decoupling threshold force gives rise to this bistability, as the low-frequency switching occurs when the probability of decoupling during each ac cycle is small but finite. We attribute the distribution in the decoupling threshold force to the range of structural configurations allowed for the quasi-1D electron lattice, which influences the strength of the WS-DL coupling. Hence, the switching rate between the ac transport modes is extremely sensitive to the microscopic properties of the electron solid.
Dynamical decoupling and recoupling of the Wigner solid to a liquid helium substrate
(2020-08-24)
Rees, David G.
;
Yeh, Sheng-Shiuan
;
Lee, Ban-Chen
;
Schnyder, Simon K.
;
Williams, Francis I. B.
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.