Quantum leap in metrology: memristors as a new standard for electrical resistance

29.10.2025

Generated by ChatGPT 4.0 (2025).

An international collaboration including IMDEA Nanociencia researchers has demonstrated that memristors can generate stable discrete resistance states, directly related to universal constants of nature.
The research opens the path for integrating intrinsic, quantum-accurate standards into next-generation chips.

Madrid, October 29^th, 2025. Researchers at IMDEA Nanociencia, together with international collaborators, have demonstrated for the first time that memristors—novel nanoscale switching devices—can provide stable resistance values directly linked to fundamental constants of nature. This paves the way for electrical units such as electrical resistance to be traced back far more simply and directly than it has been possible to date. By contrast, conventional, quantum-based measurement technology is so demanding that it can only be carried out in a few specialized laboratories worldwide.

Since 2019, all base units of the International System of Units (SI) – including the meter, 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 meter is defined by 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 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 precise, reproducible values, it requires extreme laboratory conditions—temperatures close to absolute zero and magnetic fields stronger than those in clinical MRI systems. The measurements require sophisticated cryogenic systems and strictly controlled facilities.

Memristors offer a radically different approach. Originally developed as building blocks for novel computing architectures, they exhibit switching behaviour that directly follows universal constants. Functionally, they act as programmable resistors—essentially transistors with memory. 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.

“For the first time, we have demonstrated that memristors can reliably generate discrete resistance states that are directly related to universal constants of nature—without the need for elaborate cooling systems or high magnetic fields”, says Gianluca Milano, coordinator of the european MEMQuD project that joined efforts from 15 institutes and universities across all Europe to achieve this result.

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. 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 analogous to fine grinding: so-called “electrochemical polishing”. In this process, unstable atoms are removed from the conducting filament until only a stable quantized conduction channel remains.

This approach brings into reach a concept known as “NMI-on-a-chip”—the service of a national metrology institute condensed into a microchip. In the future, this could allow a measuring device to have its reference built directly into the chip. Lengthy calibration chains—from measurements in metrology institutes, through reference resistors and precision calibrators, down 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 against the unchanging natural constant – a built-in calibration standard.

Applications range from simplified calibration procedures in industry to mobile measuring systems and portable standards for research in the field or in space. Mariela Menghini of IMDEA Nanociencia summarizes “The international collaboration including three European National Metrology Institutes was a real tour de force uniting experts in materials science, memristor technology and metrology to demonstrate that integrating intrinsic, quantum-accurate standards into next-generation chips is no longer a distant goal but an emerging reality”.

This work has been carried out at Istituto Nazionale di Ricerca Metrologica (Turin, Italy), the Forschungszentrum Jülich (Germany), the Instituto Português da Qualidade (Caparica, Portugal), the TUBITAK National Metrology Institute (Gebze, Turkey), the Universitat Autònoma de Barcelona (Spain), the Politecnico di Torino (Italy) and the Madrid Institute for Advanced Studies in Nanoscience (IMDEA Nanociencia, Spain). It has been partially funded by the European project MEMQuD (20FUN06, memqud.inrim.it), receiving funding from the European Metrology Programme for Innovation and Research (EMPIR), cofinanced by the participating states and from the European Union’s Horizon 2020 research and innovation programme.

Glossary:

Memristor: a non-linear two terminal electrical component, whose resistance changes based on the history of the current that passes through it. It´s the fourth elemental electrical component.
Conductance quantum G₀: quantized unit of electrical conductance defined as 2e²/h (e: electron charge and h: Planck constant).
Traceability: is the process of establishing a measurement's connection to the International System of Units (SI) through an unbroken chain of calibrations or comparisons, each with a stated uncertainty.

Reference

Gianluca Milano*, Xin Zheng, Fabio Michieletti, Giuseppe Leonetti, Gabriel Caballero, Ilker Oztopra, Luca Boarino, Özgür Bozat, Luca Callegaro, Natascia De Leo, Isabel Godinho, Daniel Granados, Itir Koymen, Mariela Menghini, Enrique Miranda, Luís Ribeiro, Carlo Ricciardi, Jordi Suñe, Vitor Cabral*, Ilia Valov*, A quantum resistance memristor for an intrinsically traceable International System of Units standard. Nat. Nanotech. 2025. DOI: 10.1038/s41565-025-02037-5

Link to IMDEA Nanociencia Repository: https://hdl.handle.net/20.500.12614/4109

Contact:

Dr. Mariela Menghini
Transport in Quantum Materials Group
https://nanociencia.imdea.org/transport-in-quantum-materials/home

Dr. Daniel Granados
Quantum Devices and Photonics
https://nanociencia.imdea.org/quantum-nanodevices/group-home

IMDEA Nanociencia Dissemination and Communication Office
divulgacion.nanociencia [at]imdea.org

Source: IMDEA Nanociencia.

IMDEA Nanociencia Institute is a young interdisciplinary research Centre in Madrid (Spain) dedicated to the exploration of nanoscience and the development of applications of nanotechnology in connection with innovative industries.