Observation of an Anisotropic Wigner Crystal

Abstract

We report a new correlated phase of two-dimensional charged carriers in high magnetic fields, manifested by an anisotropic insulating behavior at low temperatures. It appears in a large range of low Landau level fillings $1/3\ensuremath{\lesssim}\ensuremath{\nu}\ensuremath{\lesssim}2/3$ in hole systems confined to wide GaAs quantum wells when the sample is tilted in magnetic field to an intermediate angle. The parallel field component (${B}_{\ensuremath{\parallel}}$) leads to a crossing of the lowest two Landau levels, and an elongated hole wave function in the direction of ${B}_{\ensuremath{\parallel}}$. Under these conditions, the in-plane resistance exhibits an insulating behavior, with the resistance along ${B}_{\ensuremath{\parallel}}$ about 10 times smaller than the resistance perpendicular to ${B}_{\ensuremath{\parallel}}$. We interpret this anisotropic insulating phase as a two-component, striped Wigner crystal.