Anomalous Stability of nu=1 Bilayer Quantum Hall State

TL;DR

This paper investigates the unusual stability of the nu=1 quantum Hall state in a double-layer electron system, revealing its robustness due to spontaneous interlayer coherence, unlike other quantum Hall states.

Contribution

It demonstrates the anomalous stability of the nu=1 quantum Hall state and attributes it to spontaneous interlayer quantum coherence in a double-layer system.

Findings

nu=1 state is more stable than other QH states under density imbalance

Interlayer coherence explains the anomalous stability of the nu=1 state

Other QH states decay with imbalance, unlike nu=1

Abstract

We have studied the fractional and integer quantum Hall (QH) effects in a high-mobility double-layer two-dimensional electron system. We have compared the "stability" of the QH state in balanced and unbalanced double quantum wells. The behavior of the n=1 QH state is found to be strikingly different from all others. It is anomalously stable, though all other states decay, as the electron density is made unbalanced between the two quantum wells. We interpret the peculiar features of the nu=1 state as the consequences of the interlayer quantum coherence developed spontaneously on the basis of the composite-boson picture.