Observation of Dynamical Ordering in a Confined Wigner Crystal

Abstract

We present measurements of the conduction of nondegenerate free electrons along a low-dimensional channel at low temperatures, using surface-state electrons on liquid helium in novel microelectronic devices. Above 1 K, the electrons form an ideal classical Drude conductor. Below 1 K, Coulomb interactions produce electronic spatial order, leading to strong non-Ohmic effects and negative differential conductivity. Evidence is presented for self-organized current filaments in the channel, created by a nonequilibrium phase transition. Periodic conductance oscillations suggest an anisotropic spatial order with lines of electrons along the channel edges.

Statistical, collective, and critical phenomena of classical one-dimensional disordered Wigner lattices

“…Our analysis introduces mathematical methods for analytically evaluating a certain class of lattice sums that have traditionally been performed numerically. Recently, Wigner crystals in lower dimensions have experienced a resurgence in interest by both experimentalists and theorists alike 10 , in systems such as low density quantum wires and various soft condensed matter systems 11 . Furthermore, the precise wavevector dependence of the eigenfrequencies have important consequences for many physically pertinent quantities such as the dynamical response functions, and thus the results of this paper provide some degree of analytical control in future investigations of Wigner Crystals that emphasize the role of long-ranged interactions.…”

Generic properties of a quasi-one-dimensional classical Wigner crystal

“…8͒ at low enough temperatures and densities when the potential energy overwhelms the kinetic energy. Indeed, evidence of such a type of transition was found very recently 3 in experiments on electrons on the surface of liquid Helium, where the electrons were confined by metallic gates and exhibited dynamical ordering in the form of filaments. This particular experiment posed many interesting questions regarding the nature of the transition to WC, its density dependence, and the melting.…”

“…A class of quantum anisotropic systems exhibiting ''stripe'' behavior appears in the quantum Hall effect, 1 in oxide manganites, and in high-T c superconductors, 2 where electronic strong correlations are responsible for the formation of these inhomogeneous phases. Another class of confined quasi-one-dimensional ͑Q1D͒ geometries appears in many diverse fields of research and some typical and important examples from the experimental point of view are: electrons on liquid Helium, 3,4 microfluidic devices, 5 colloidal suspensions, 6 and confined dusty plasma. 7 A major phenomenon which is expected to occur in charged particles interacting via a Coulomb or screened Coulomb potential is Wigner crystallization ͑WC͒ ͑Ref.…”

Formation of defects in multirow Wigner crystals

“…The three-dimensional Wigner crystal and its two-dimensional counterpart have been extensively studied, and there exist beautiful experimental realizations of the latter using electrons trapped on the surface of liquid Helium [2][3][4][5] . More recently, Wigner crystallization in one dimension has received renewed interest [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] ; for recent reviews see Refs.…”