Compressible Phase of a Double-Layer Electron System with Total Landau-Level Filling Factor One-Half

TL;DR

This paper models a double-layer electron system at filling factor 1/2, revealing a new diffusive mode and an attractive pairing interaction that could explain fractional quantum Hall effects in such systems.

Contribution

It introduces a new diffusive mode and pairing interaction in the double-layer system, extending previous single-layer models to better understand fractional quantum Hall phenomena.

Findings

Discovery of a low-lying diffusive mode in the double-layer system

Identification of an attractive pairing interaction between layers

Potential explanation for fractional quantum Hall effects in double layers

Abstract

Following recent work of Halperin, Lee, and Read, and Kalmeyer and Zhang, a double-layer electron system with total Landau-level filling factor $\nu=1/2$ is mapped onto an equivalent system of fermions in zero average magnetic field interacting via a Chern-Simons gauge field. Within the random-phase approximation a new, low-lying, diffusive mode, not present in the $\nu=1/2$ single-layer system, is found. This mode leads to more singular low-energy scattering than appears in the single layer system, and to an attractive pairing interaction between fermions in different layers which grows stronger as the layer spacing is decreased. The possible connection between this pairing interaction and the experimentally observed fractional quantum Hall effect in double-layer systems is discussed.