Topological Excitations in Double-Layer Quantum Hall systems

TL;DR

This paper investigates how quantum fluctuations affect topological excitations in double-layer quantum Hall systems, showing that increased layer separation can destroy interlayer coherence and the quantum Hall effect, with theoretical results aligning with experiments.

Contribution

It provides a calculation of the renormalized isospin stiffness due to quantum fluctuations, elucidating the conditions under which the quantum Hall effect disappears.

Findings

Quantum fluctuations reduce interlayer coherence as layer separation approaches critical value.

Calculated activation energy of topological excitations agrees qualitatively with experimental data.

Interlayer coherence and quantum Hall effect are sensitive to quantum fluctuations.

Abstract

Double-layer quantum Hall systems with spontaneous broken symmetry can exhibit a novel manybody quantum Hall effect due to the strong interlayer coherence. When the layer separation becomes close to the critical value, quantum fluctuations can destroy the interlayer coherence and the quantum Hall effect will disappear. We calculate the renormalized isospin stiffness $\rho_s$ due to quantum fluctuations within the Hartree-Fock-RPA formalism. The activation energy of the topological excitations thus obtained demonstrates a nice qualitative agreement with recent experiment.