Quantum Hall Ferromagnets

TL;DR

This paper investigates the magnetotransport properties of $ u=1/m$ quantum Hall states in bilayer systems, revealing their behavior as easy plane quantum ferromagnets and uncovering a novel topological transport phenomenon.

Contribution

It introduces a new understanding of quantum Hall ferromagnets' transport via a spin-charge relation and phase slippage, highlighting topological constants in their dynamics.

Findings

Transport combines Hall and time-dependent quantized components.

Phase slippage in spacetime leads to topological quantization.

The system exhibits a novel topological transport mechanism.

Abstract

It is pointed out recently that the $\nu=1/m$ quantum Hall states in bilayer systems behave like easy plane quantum ferromagnets. We study the magnetotransport of these systems using their ``ferromagnetic" properties and a novel spin-charge relation of their excitations. The general transport is a combination of the ususal Hall transport and a time dependent transport with $quantized$ time average. The latter is due to a phase slippage process in $spacetime$ and is characterized by two topological constants. (Figures will be provided upon requests).