Sliding of an electron crystal of finite size on the surface of superfluid He4 confined in a microchannel

Abstract

We present a new study of the nonlinear transport of a two-dimensional electron crystal on the surface of liquid helium confined in a 10-µm-wide channel in which the effective length of the crystal can be varied from 10 to 215 µm. At low driving voltages, the moving electron crystal is strongly coupled to deformation of the liquid surface arising from resonant excitation of surface capillary waves, ripplons, while at higher driving voltages the crystal decouples from the deformation. We find strong dependence of the decoupling threshold of the driving electric field acting on the electrons, on the size of the crystal. In particular, the threshold electric field significantly decreases when the length of the crystal becomes shorter than 25 µm. We explain this effect as arising from weakening of surface deformations due to radiative loss of resonantly-excited ripplons from an electron crystal of finite size, and we account for the observed effect using an instructive analytical model.

The movement of a one-dimensional Wigner solid explained by a modified Frenkel-Kontorova model

“…Confining the SSE in capillarycondensed micro-channel structures is practical for investigating nonlinear electron transport and phase transitions. The strongly-correlated WS phase gives rise to many interesting phenomena, such as the re-entrant melting of quasi-1D electron crystals [10][11][12], stick-slip motion of a WS [13,14], the bistable transport properties of a quasi-1D WS [15], the finite-size effect of WSs on sliding transition [16,17], and the loss of the long-range positional order of a quasi-1D WS in the presence of an external periodic potential [18].…”

“…At least, if one exposes the WS to an external electric field then the redistribution of the electrons can be recorded as a current [8,16,17,24].…”

“…We use here a modified Frenkel-Kontorova model, see Section 2. All electrons subject to the Coulomb force. However, the electrons in both reservoirs before and after the channel of the chain, in the experiments [17,18], press the chain into a pattern with fixed distances. In a 1D-chain the Coulomb potential between electrons is screened by the presence of other electrons [28].…”

Static and dynamic phases of a Tonks–Girardeau gas in an optical lattice

“…Quantum phase transitions in these systems can be probed by switching the control parameter across a critical point [13][14][15][16][17][18]. Additionally, the transport properties of such systems can be linked to classical models of friction which describe stick-slip motion between two surfaces [19][20][21][22][23], an effect which has been recently observed [24][25][26]. In fact, precise control of the competing length scales between the two surfaces can be used to effectively control the amount of friction present [27] and can give insights into designing frictionless dynamical processes for quantum systems.…”

Static and dynamic phases of a Tonks-Girardeau gas in an optical lattice

“…Quantum phase transitions in these systems can be probed by switching the control parameter across a critical point [13,14,15,16,17,18]. Additionally, the transport properties of such systems can be linked to classical models of friction which describe stick-slip motion between two surfaces [19,20,21,22,23], an effect which has been recently observed [24,25,26]. In fact, precise control of the competing length scales between the two surfaces can be used to effectively control the amount of friction present [27] and can give insights into designing frictionless dynamical processes for quantum systems.…”