A tunable Fabry-Pérot quantum Hall interferometer in graphene

Area of Science:

• Condensed Matter Physics
• Quantum Hall Effect
• Materials Science

Background:

• Electron interferometry in quantum Hall (QH) edge channels is crucial for understanding anyonic excitations.
• Semiconductor heterostructures suffer from charging effects that hinder Aharonov-Bohm interference in QH interferometers.
• Advanced charge-screening methods are often required to overcome these limitations in semiconductor-based systems.

Purpose of the Study:

• To investigate high-mobility monolayer graphene as a material for Fabry-Pérot quantum Hall interferometry.
• To demonstrate the feasibility of performing QH interferometry in graphene without detrimental charging effects.
• To explore the potential of graphene for probing anyonic excitations in QH states.

Main Methods:

• Fabrication of graphene devices with gate-tunable quantum point contacts.
• Utilizing the edge channels of the zeroth Landau level in monolayer graphene.
• Performing Fabry-Pérot quantum Hall interferometry and measuring Aharonov-Bohm interference patterns.

Main Results:

• Observed high-visibility Aharonov-Bohm interference in graphene QH interferometers, free from charging effects.
• Demonstrated wide tunability of interference patterns via electrostatic gating and magnetic fields.
• Achieved a coherence length of 10 micrometers at 0.02 K, enabling double Fabry-Pérot interferometry.

Conclusions:

• High-mobility monolayer graphene is a promising alternative material for quantum Hall interferometry due to its lack of charging effects.
• Graphene-based QH interferometers exhibit tunable, high-visibility interference, agreeing with theoretical predictions.
• Future research with graphene devices could unlock investigations into anyonic excitations in fractional QH states.