Integer Quantum Hall Effect in Double-Layer Systems

TL;DR

This paper investigates the localization properties and phase transitions in double-layer quantum Hall systems under strong magnetic fields, using numerical and transfer matrix methods to analyze microscopic and phenomenological models.

Contribution

It provides new insights into the crossover behavior and the limitations of network models in describing localization in double-layer quantum Hall systems.

Findings

Identification of a crossover regime with increased correlation length exponent

Microscopic calculations suggest limitations of network models for certain regimes

Numerical results highlight the impact of interlayer tunneling on localization

Abstract

We consider the localization of independent electron orbitals in double-layer two-dimensional electron systems in the strong magnetic field limit. Our study is based on numerical Thouless number calculations for realistic microscopic models and on transfer matrix calculations for phenomenological network models. The microscopic calculations indicate a crossover regime for weak interlayer tunneling in which the correlation length exponent appears to increase. Comparison of network model calculations with microscopic calculations casts doubt on their generic applicability.