Graphene-Based Quantum Hall Interferometer with Self-Aligned Side Gates

Area of Science:

• Condensed matter physics
• Materials science
• Nanotechnology

Background:

• Graphene's zero band gap complicates the fabrication of high-quality quantum point contacts (QPCs).
• Conventional split-gate methods lead to p-n interfaces that short-circuit QPCs, hindering graphene quantum Hall Fabry-Pérot interferometer development.
• Recent advances enabled QPCs using the resistive ν = 0 state, but simpler fabrication is needed.

Purpose of the Study:

• To present a straightforward fabrication method for graphene quantum point contacts (QPCs).
• To demonstrate the operation of these QPCs in the quantum Hall regime.
• To utilize the fabricated QPCs for constructing and investigating a quantum Hall interferometer.

Main Methods:

• Etching a narrow trench in the graphene sheet to isolate the conducting channel.
• Fabricating self-aligned graphene side gates adjacent to the etched trench.
• Characterizing individual QPC operation in the quantum Hall regime.

Main Results:

• Successful fabrication of graphene QPCs using a simple trench-etching technique.
• Demonstrated reliable operation of individual QPCs within the quantum Hall regime.
• Utilized the fabricated QPCs to construct a functional quantum Hall interferometer.

Conclusions:

• The trench-etching method provides a simple and effective route to high-quality graphene QPCs.
• This technique overcomes previous limitations, facilitating the study of quantum phenomena in graphene.
• The developed QPCs are suitable for building and exploring quantum Hall interferometers.