Initial NIST AC QHR Measurements.

Area of Science:

• Electrical Metrology
• Quantum Phenomena
• Solid State Physics

Background:

• The quantized Hall resistance (QHR) is a fundamental standard in electrical metrology.
• Accurate measurement of QHR, especially under AC conditions, is crucial for advancing metrological capabilities.
• Existing methods often require complex setup changes, limiting efficiency and precision.

Purpose of the Study:

• To demonstrate simultaneous measurement of DC and AC QHR without altering sample probe connections.
• To report AC QHR values obtained using a four-terminal-pair measurement technique.
• To assess the frequency dependence of QHR measurements and their convergence to DC values.

Main Methods:

• Utilized single-series and quadruple-series connections outside the sample probe for measurements during a single cooldown.
• Performed AC QHR measurements from 0 Hz to 5500 Hz at 20 µA.
• Employed a bridge setup and exchanged the positions of the QHR device and reference resistor to mitigate AC bridge effects.

Main Results:

• Achieved measurements of DC and AC QHR guideline properties and values without changing probe lead connections.
• Reported AC QHR values that converge to the DC QHR value within ±1 part in 10(7) uncertainties using four-terminal-pair measurements.
• Demonstrated the feasibility of these measurements even with a poor-quality QHR device, suggesting potential for higher precision with improved devices.

Conclusions:

• Simultaneous DC and AC QHR measurements are feasible without probe reconfiguration, enhancing measurement efficiency.
• Four-terminal-pair AC QHR measurements show convergence to DC values, validating the technique for resistance metrology.
• The methodology holds promise for improved uncertainty in AC QHR measurements across a range of frequencies.