Coupling between Quantum Hall Edge Channels on Opposite Sides of a Hall Bar

TL;DR

This study explores the capacitive coupling between quantum Hall edge channels on opposite sides of a Hall bar, revealing how localized states influence the coupling and how it varies across quantum Hall and non-quantum Hall states.

Contribution

It provides experimental evidence of capacitive coupling between opposite edge channels and analyzes how localized states affect this coupling in different quantum Hall regimes.

Findings

Capacitive coupling causes a peak and dip in current signals.

Localized states influence the capacitance and coupling strength.

Coupling behavior transitions between quantum Hall and non-QH states.

Abstract

We investigate the coupling between quantum Hall (QH) edge channels (ECs) located at opposite sides of a 50-um-wide Hall bar by exciting a charged wavepacket in one EC and detecting time-dependent current in the other EC. In a QH state, the current shows a peak followed by a dip, demonstrating the existence of capacitive coupling across the incompressible two-dimensional electron system (2DES). The observed magnetic field dependence of the amplitude and time delay of the current suggests that the capacitance is affected by the presence of localized states. We also show that the dominant manner of the coupling changes gradually as the system changes between the QH and non-QH states.