Browsing by Author "Rees, David G."

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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.
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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.
Reentrant Melting of a Classical Quasi-One-Dimensional Wigner Crystal on the Surface of Liquid Helium
(2013-12-01)
Rees, David G.
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Ikegami, Hiroki
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Kono, Kimitoshi
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物理研究所
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Institute of Physics
We present transport measurements of electrons on the surface of liquid helium confined to a microscopic channel, the effective width of which can be controlled electrostatically. Above 1 K the electron system is liquid-like and the conductance varies smoothly with the channel width. At lower temperatures the system forms a classical quasi-one-dimensional Wigner crystal ( WC). Close to the WC melting temperature, the current oscillates as the channel width is varied, due to reentrant melting as recently reported [H. Ikegami, H. Akimoto, D. G. Rees, and K. Kono: Phys. Rev. Lett. 109 ( 2012) 236802]. In the WC regime we observe Bragg-Cherenkov ripplon scattering, a signature of strong spatial electron order, for both the widely open channel and the single electron chain.
Stick-Slip Motion of the Wigner Solid on Liquid Helium
(2016-05-16)
Rees, David G.
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Beysengulov, Niyaz R.
;
Lin, Juhn-Jong
;
Kono, Kimitoshi
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電子物理學系
We present time-resolved transport measurements of a Wigner solid (WS) on the surface of liquid helium confined in a micron-scale channel. At rest, the WS is "dressed" by a cloud of quantized capillary waves (ripplons). Under a driving force, we find that repeated WS-ripplon decoupling leads to stick-slip current oscillations, the frequency of which can be tuned by adjusting the temperature, pressing electric field, or electron density. The WS on liquid He is a promising system for the study of polaronlike decoupling dynamics.
Structural order and melting of a quasi-one-dimensional electron system
(2016-07-29)
Rees, David G.
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Beysengulov, Niyaz R.
;
Teranishi, Yoshiaki
;
Tsao, Chun-Shuo
;
Yeh, Sheng-Shiuan
We investigate the influence of confinement on the positional order of a quasi-1D electron system trapped on the surface of liquid helium. We find evidence that the melting of the Wigner solid (WS) depends on the confinement strength, as well as electron density and temperature. A reentrant solid-liquid-solid transition is observed for increasing electron density under constant electrostatic confinement. As the electron row number N-y changes, varying commensurability results in a modulation of the WS order, even when N-y is large (several tens). This is confirmed by Monte Carlo simulations.