Tunable tunnel coupling in a double quantum antidot with cotunneling via localized state

TL;DR

This paper introduces a method to tune tunnel coupling between quantum antidots in the quantum Hall regime using cotunneling via a localized state, enabling control over quantum interactions.

Contribution

It presents a novel scheme for tunable tunnel coupling in quantum antidots through cotunneling, validated by experimental and numerical analysis.

Findings

Tunable tunnel coupling achieved via localized state cotunneling.

Anti-crossing of Coulomb blockade peaks confirms tunability.

Numerical simulations support experimental results.

Abstract

Controlling tunnel coupling between quantum antidots (QADs) in the quantum Hall (QH) regime is problematic. We propose and demonstrate a scheme for tunable tunnel coupling between two QADs by utilizing a cotunneling process via a localized state as a third QAD. The effective tunnel coupling can be tuned by changing the localized level even with constant nearest-neighbor tunnel couplings. We systematically study the variation of transport characteristics in the effectively triple QAD system at the Landau level filling factor $\nu =2$. The tunable tunnel coupling is clarified by analyzing the anti-crossing of Coulomb blockade peaks in the charge stability diagram, in agreement with numerical simulations based on the master equation. The scheme is attractive for studying coherence and interaction in QH systems.