Wigner Crystallization in a Quasi-3D Electronic System

TL;DR

This paper reports the discovery of a new quasi-3D electron solid phase induced by high magnetic fields in a system where electrons are confined to two dimensions, revealing complex electron interactions beyond traditional 2D Wigner crystals.

Contribution

The study uncovers a novel quasi-3D electron solid phase under high magnetic fields, expanding understanding of electron crystallization in low-dimensional systems.

Findings

Identification of a new insulating quantum phase at high magnetic fields

Evidence suggesting the phase is a quasi-3D electron solid

Observation of electron crystallization beyond traditional 2D Wigner crystals

Abstract

When a strong magnetic field is applied perpendicularly (along z) to a sheet confining electrons to two dimensions (x-y), highly correlated states emerge as a result of the interplay between electron-electron interactions, confinement and disorder. These so-called fractional quantum Hall (FQH) liquids form a series of states which ultimately give way to a periodic electron solid that crystallizes at high magnetic fields. This quantum phase of electrons has been identified previously as a disorder-pinned two-dimensional Wigner crystal with broken translational symmetry in the x-y plane. Here, we report our discovery of a new insulating quantum phase of electrons when a very high magnetic field, up to 45T, is applied in a geometry parallel (y-direction) to the two-dimensional electron sheet. Our data point towards this new quantum phase being an electron solid in a "quasi-3D" configuration induced by orbital coupling with the parallel field.