Single-File Transport of Classical Electrons on the Surface of Liquid Helium

Abstract

Electrons trapped on the surface of liquid helium form a model two-dimensional system. Because the electron density is low (~ 109 cm-2) and the Coulomb interaction between the electrons is essentially unscreened, the system can be regarded as a classical analogue of the degenerate Fermi gas. Electrons on helium have therefore long been used to study many-body transport phenomena in two dimensions. Here we review recent experiments investigating the transport of electrons on helium through microscopic constrictions formed in microchannel devices. Two constriction geometries are studied; short saddle-point constrictions and long constrictions in which the length greatly exceeds the width. In both cases, the constriction width can be tuned electrostatically so that the electrons move in single file. As the width of the short constriction is increased, a periodic suppression of the electron current is observed due to pinning for commensurate states of the electron lattice. A related phenomenon is observed for the long constriction whereby the quasi-one-dimensional Wigner lattice exhibits reentrant melting as the number of electron chains increases. Our results demonstrate that electrons on helium are an ideal system in which to study many-body transport in the limit of single-file motion. [Formula: see text] Special Issue Comments: This article presents experimental results on the dynamics of classical electrons moving on the surface of liquid helium in narrow channels with constrictions, with a focus on the "quantum wire", i.e. single file, regime. This article is related to the Special Issue articles about advanced statistical properties in single file dynamics34 and the mathematical results on electron dynamics in liquid helium.35