| Nov 03, 2025 |
Researchers show nanoscale memristors can calibrate electrical resistance without complex labs or extreme conditions, opening metrological uses in electronics.
(Nanowerk News) An international research collaboration with the involvement of the UAB demonstrates for the first time that memristors, electronic devices at the nanoscale, can easily calibrate electrical resistance for certain applications without requiring large and complex laboratories working at extreme temperatures and very high magnetic fields.
|
|
The work, published in Nature Nanotechnology (“A quantum resistance memristor for an intrinsically traceable International System of Units standard”), explores for the first time the metrological applications of these devices in calibration procedures of electronic systems.
|
|
Measuring electrical resistance with maximum precision to be used as a standard in metrology requires complex laboratories at temperatures close to the absolute zero and magnetic fields that are more intense than those used in clinical magnetic resonance imaging.
|
|
International research under the framework of the European project MEMQuD, which included the involvement of UAB Department of Electronic Engineering professors Enrique Miranda and Jordi Suñé, demonstrates that memristors can provide stable resistance values directly linked to fundamental constants of nature. Thus, they can become a new much simpler standard than current systems for calibrations of this magnitude.
|
Measurement standards based on constants of nature
|
|
Since 2019, all base units of the International System of Units (SI)—including the metre, second, and kilogram—have been based on fundamental natural constants. For example, the kilogram, which was once based on the “prototype kilogram,” is now linked to Planck’s constant h. A metre is defined with respect to the speed of light, and a second by the oscillation of the cesium atom.
|
|
Thanks to laser interferometers and atomic clocks, units of length and time can be verified relatively easily worldwide. The situation is quite different for physical quantities such as mass and electrical units. Their metrological traceability is so complex that the measurements are feasible only in a handful of national metrology institutes.
|
|
Until now, the quantum Hall effect has served as the standard for electrical resistance. While it provides highly precise and reproducible values, it requires extreme laboratory conditions, i.e. temperatures close to absolute zero and high magnetic fields. The measurements require sophisticated cryogenic systems and strictly controlled facilities.
|
Memristors as standard resistance measurement systems
|
|
Memristors offer a radically different approach. Originally developed as building blocks for novel computing architectures, such as non-volatile memories and neuromorphic circuits emulating computations in the brain, they exhibit a switching behavior that directly follows universal constants.
|
|
Functionally, they act as programmable resistors—essentially resistors with memory. This resistance can be changed by applying external voltages or currents. Conductive nanofilaments of individual silver atoms forms inside them. By applying electrical bias, these filaments can be adjusted with atomic precision so that their conductance changes not continuously, but in discrete quantum steps.
|
|
“We have confirmed that memristors can reliably generate discrete resistance states that are directly related to universal constants of nature. In 1998, our group already revealed these quantum effects for the first time in the dielectric breakdown of thin insulators. For certain applications, these devices can be used for calibration without the need of complex cooling systems or high magnetic fields”, says UAB professor Enrique Miranda.
|
A national metrology institute condensed into one microchip
|
|
This approach makes it possible to talk about a concept known as “NMI-in-a-chip”: the service of a national metrology institute condensed into a microchip. In the future, this could mean that a measuring device has its resistance reference built-in directly into the chip. Lengthy calibration chains—from measurements in metrology institutes, reference resistors and precision calibrators, to the calibration of end-user devices—would no longer be necessary. Instead of repeatedly sending a multimeter to the calibration laboratory, it could check itself internally, i.e. a built-in calibration standard.
|
Applications in research and industries
|
|
Applications range from simplified calibration procedures in industry to mobile measuring systems and portable standards for research in the field or in space. “We are at the beginning of a paradigm shift—moving away from complex large-scale facilities towards intrinsic, quantum-accurate standards that can be integrated into any chip”, says UAB professor Jordi Suñé.
|
Quantified electrical conductance
|
|
The foundation of this work is the quantized electrical conductance G₀, derived from Planck’s constant h and the elementary charge e. In the experiments, memristors were reproducibly programmed in air at room temperature into stable conductance states of exactly 1·G₀ and 2·G₀, maintained over extended periods of time. Measurements taken at participating research institutes in Italy, Germany, Spain, Turkey, and Portugal revealed a deviation of 3.8 percent for 1·G₀ and 0.6 percent for 2·G₀. The key lies in a process known as “electrochemical polishing”. In this process, unstable atoms are removed from the conducting filament until only a stable quantized conduction channel remains.
|
