Wigner solid pinning modes tuned by fractional quantum Hall states of a nearby layer

TL;DR

This study investigates how the pinning modes of a Wigner solid in a bilayer 2D electron system are affected by the formation of fractional quantum Hall states in a nearby layer, revealing strong coupling mediated by screening.

Contribution

It demonstrates the influence of fractional quantum Hall states on Wigner solid pinning modes in a bilayer system, highlighting interlayer coupling effects.

Findings

Pinning mode frequencies evolve with FQHS formation

Strong coupling between Wigner solid and FQHS states

Screening mediates interlayer interactions

Abstract

We study a bilayer system hosting exotic many-body states of two-dimensional electron systems (2DESs) in close proximity but isolated from one another by a thin barrier. One 2DES has low electron density and forms a Wigner solid (WS) at high magnetic fields. The other has much higher density and, in the same field exhibits fractional quantum Hall states (FQHSs). The WS manifests microwave resonances which are understood as pinning modes, collective oscillations of the WS within the small but finite ubiquitous disorder. Our measurements reveal a striking evolution of the pinning mode frequencies of the WS layer with the formation of the FQHSs in the nearby layer, evincing a strong coupling between the WS pinning modes and the state of the 2DES in the adjacent layer, mediated by screening.