Observation of An Anisotropic Wigner Crystal

TL;DR

This paper reports the discovery of an anisotropic insulating phase in two-dimensional hole systems under high magnetic fields, interpreted as a striped Wigner crystal, revealing new correlated electron behavior.

Contribution

It presents the observation of an anisotropic Wigner crystal phase induced by tilted magnetic fields in 2D hole systems, a novel state not previously characterized.

Findings

Anisotropic insulating behavior observed near ν=1/2 in wide GaAs quantum wells.

Resistance along the magnetic field direction is over 10 times smaller than perpendicular.

The phase is interpreted as a striped 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 near Landau level filling factor $\nu=1/2$ 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 ($B_{||}$) leads to a crossing of the lowest two Landau levels, and an elongated hole wavefunction in the direction of $B_{||}$. Under these conditions, the in-plane resistance exhibits an insulating behavior, with the resistance along $B_{||}$ more than 10 times smaller than the resistance perpendicular to $B_{||}$. We interpret this anisotropic insulating phase as a two-component, striped Wigner crystal.