Wigner solids of wide quantum wells near Landau filling $\nu=1$

TL;DR

This study investigates multiple Wigner solid phases in wide quantum wells near Landau filling factor 1 using microwave spectroscopy, revealing three distinct phases and their stabilization mechanisms.

Contribution

It identifies and characterizes three different Wigner solid phases in wide quantum wells near $ u=1$, including a novel phase S1A of excitations of the Halperin-Laughlin state.

Findings

Three distinct Wigner solid phases (S1, S2, S1A) identified.

S2 stabilized by Zeeman energy at certain densities and tilt angles.

S1A is a newly observed phase of excitations of the $ u=1$ state.

Abstract

Microwave spectroscopy within the Landau filling ($\nu$) range of the integer quantum Hall effect (IQHE) has revealed pinning mode resonances signifying Wigner solids (WSs) composed of quasi-particles or -holes. We study pinning modes of WSs in wide quantum wells (WQWs) for $ 0.8\le\nu\le1.2$, varying the density, $n$, and tilting the sample by angle $\theta$ in the magnetic field. Three distinct WS phases are accessed. One phase, S1, is phenomenologically the same as the WS observed in the IQHEs of narrow QWs. The second phase, S2, exists at $\nu$ further from $\nu=1$ than S1, and requires a sufficiently large $n$ or $\theta$, implying S2 is stabilized by the Zeeman energy. The melting temperatures of S1 and S2, estimated from the disappearance of the pinning mode, show different behavior vs $\nu$. At the largest $n$ or $\theta$, S2 disappears and the third phase, S1A, replaces S1, also exhibiting a pinning mode. This occurs as the WQW $\nu=1$ IQHE becomes a two-component, Halperin-Laughlin $\pone$ state. We interpret S1A as a WS of the excitations of $\pone$, which has not been previously observed.