Double-layer quantum Hall antiferromagnetism at filling fraction nu=2/(odd integer)

TL;DR

This paper develops a low energy theoretical framework for double-layer quantum Hall systems at specific fractional fillings, revealing phase transitions and magnetic order properties relevant to experimental observations.

Contribution

It introduces a low energy action capturing phase behavior and critical phenomena in double-layer quantum Hall systems at odd-integer filling fractions.

Findings

Identifies a canted spin order phase induced by interlayer exchange.

Calculates the critical temperature for the Kosterlitz-Thouless transition.

Discusses implications for light scattering experiments at filling fraction 2.

Abstract

A low energy action for double-layer quantum Hall systems at filling fractions $\nu = 2/m$ ($m$ an odd integer) is introduced. Interlayer antiferromagnetic exchange induces a phase with canted spin order, and also a spin-singlet phase. Universal properties of zero and finite temperature transitions are obtained. We compute the critical temperature at which the canted order vanishes in a Kosterlitz-Thouless transition. Implications for recent light scattering experiments at $\nu = 2$ are noted.