Development of gateless quantum Hall checkerboard p-n junction devices

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Electronics

Background:

• The quantum Hall effect (QHE) is a key phenomenon in condensed matter physics, observed in 2D electron systems under strong magnetic fields.
• Accurate measurements of QHE resistance are crucial for metrology and fundamental research.
• Graphene's unique electronic properties offer potential for novel QHE device applications.

Purpose of the Study:

• To measure fractional multiples of the quantized Hall resistance using novel graphene devices.
• To demonstrate the feasibility of fabricating graphene p-n junction devices for quantum Hall resistance measurements.
• To explore the potential for scalable manufacturing of these devices.

Main Methods:

• Fabrication of millimetre-scale graphene p-n junction devices with multiple current terminals.
• Measurement of quantized Hall resistance plateaus, specifically at ν = 2.
• Numerical simulation using LTspice circuit simulator to validate device performance.
• Exploration of more complex device designs through simulation.

Main Results:

• Successful measurement of fractional multiples of the quantized Hall resistance (R_H ≈ 12906 Ω).
• Demonstrated agreement between experimental measurements and LTspice simulations.
• Identified the operational parameter space for quantum Hall resistance checkerboard devices.
• Indicated feasibility of scaling p-n junction fabrication using ultraviolet lithography.

Conclusions:

• Graphene p-n junction devices are effective for measuring quantized Hall resistance.
• Standard ultraviolet lithography offers an efficient method for scalable graphene device manufacturing.
• These advancements pave the way for practical applications of quantum Hall effect devices.