Spin Mode-Switching at the Edge of a Quantum Hall System

TL;DR

This paper reports a novel exchange-driven spin mode-switching phenomenon at the edge of a quantum Hall system, which occurs abruptly as the edge potential softens, with clear experimental signatures in transport.

Contribution

It reveals a new exchange-driven edge mode reordering in quantum Hall states, distinct from known charge-driven reconstructions, and demonstrates its robustness and experimental signatures.

Findings

Edge mode ordering switches abruptly at ν=3 with softer potentials

The phenomenon is driven by exchange effects, not charging effects

Experimental signatures are observable in transport measurements

Abstract

Quantum Hall states can be characterized by their chiral edge modes. Upon softening the edge potential, the edge has long been known to undergo spontaneous reconstruction driven by charging effects. In this paper we demonstrate a qualitatively distinct phenomenon driven by exchange effects, in which the ordering of the edge modes at $\nu=3$ switches abruptly as the edge potential is made softer, while the ordering in the bulk remains intact. We demonstrate that this phenomenon is robust, and has many verifiable experimental signatures in transport.