Researchers at NIST’s Physical Measurement Laboratory, alongside international academic partners, are developing a new quantum-based standard for measuring electrical resistance (the ohm). This protocol relies on the quantum Hall effect, a phenomenon where certain materials display perfectly predictable resistance when cooled and exposed to a magnetic field. Currently, global resistance standards use complex semiconductor chips that require expensive, high-strength superconducting magnets. The NIST team is transitioning toward graphene—a single-atom-thick carbon material—because it can produce these stable quantum measurements at lower magnetic fields and higher temperatures, which could significantly reduce equipment costs and expand access to precision electrical calibration worldwide.
To make this shift practical, the team solved a major manufacturing hurdle: traditional cleaning methods leave chemical residues that ruin graphene’s performance. Their new approach coats the material with a thin layer of gold during fabrication, then carefully strips it away using a mild acid wash. This process not only leaves the graphene completely clean but also naturally fine-tunes its electrical properties, enabling clear quantum resistance readings with standard laboratory magnets. The findings have been submitted for peer review and remain in the research phase. While no fixed rollout date has been set, ongoing studies on graphene’s unique quantum behavior are expected to eventually lead to commercial devices that could replace current standards within the next few years.
Source: https://www.nist.gov/news-events/news/2014/04/developing-gold-standard-hall-resistance
Keywords: graphene, quantum Hall effect, electrical resistance standards
