Evidence for a new symmetry breaking mechanism reorienting quantum Hall nematics

TL;DR

This study reveals a new symmetry breaking mechanism in quantum Hall nematics where in-plane magnetic fields reorient stripe phases, challenging existing theories and suggesting complex interactions between native and external symmetry-breaking influences.

Contribution

The paper uncovers a novel $B_lat$-induced symmetry breaking mechanism that reorients quantum Hall stripe phases, contradicting previous understanding of magnetic field effects.

Findings

Stripe phases reorient perpendicular to $B_lat$ at moderate fields.

Further increase in $B_lat$ reorients stripes back to their native direction.

Stripes align parallel to $B_lat$ regardless of initial orientation.

Abstract

We report on the effect of in-plane magnetic field $B_\parallel$ on stripe phases in higher ($N=2,3$) Landau levels of a high-mobility 2D electron gas. In accord with previous studies, we find that a modest $B_\parallel$ applied parallel to the native stripes aligns them perpendicular to it. However, upon further increase of $B_\parallel$, stripes are reoriented back to their native direction. Remarkably, applying $B_\parallel$ perpendicular to the native stripes also aligns stripes parallel to it. Thus, regardless of the initial orientation of stripes with respect to $B_\parallel$, stripes are ultimately aligned \emph{parallel} to $B_\parallel$. These findings provide evidence for a $B_\parallel$-induced symmetry breaking mechanism which challenge current understanding of the role of $B_\parallel$ and should be taken into account when determining the strength of the native symmetry breaking potential. Finally, our results might indicate nontrivial coupling between the native and external symmetry breaking fields, which has not yet been theoretically considered.