Towards an easier realisation of the ohm with the quantum anomalous Hall effect

Quantum Hall Effect (QHE) is the basis of the realisation of the SI unit of electrical resistance, the ohm. Present QHE devices require low temperatures and high magnetic fields to operate. The Quantum Anomalous Hall effect (QAHE) in topological insulators is a good candidate to simplify the realisation of the resistance unit and the development of a ‘quantum electrical metrology toolbox’ for universal adoption of quantum electrical SI standards, beyond just the NMIs.

The Joint Research Project QuAHMET — Quantum anomalous Hall effect materials and devices for metrology of the European Partnership on Metrology . European Partnerships are a key implementation tool of the European Commission’s Horizon Europe.
The aim of the project is to investigate and implement novel technologies for the development of QAHE devices and measurement systems for metrology, by performing traceable measurement and characterisation of QAHE materials as devices and primary resistance standard candidates.
The project is exploring, understanding, and implementing a scientifically grounded methodology for developing metrology grade QAHE devices, by focussing on the improvement of the growth techniques of magnetically doped topological insulator (TI) optimising the material properties for the QAHE, the investigation of electronic, structural, magnetic, and magneto-electronic properties of the samples, and of the limitation conditions of QAHE (expecially temperature and current), by employing also scanning probes and magnetometry techniques at low temperatures. The NMIs involved will be in charge of the development and application of accurate measurement techniques to perform a detailed metrological assessment of the optimised QAHE devices at low-to-zero applied magnetic field.

The consortium consists of 14 partners and gathers 7 leading European national metrology institutes (NMIs), a Japanese NMI for metrology, complemented by 6 globally recognized institutes from academia and applied research.
The project aims to connect with and impact on NMIs and calibration centers, academia, T&M industry and end users interested in applications, such as spintronics and topological quantum computing and advance the research and progress in the field of TIs. The project started in June 2024 and the poster will report on its advancements and results.

The project is open to collaborations and interest from stakeholders. You can connect to the project via its website (sites.google.com/inrim.it/quahmet/home), LinkedIn group (www.linkedin.com/groups/8824119/) and YouTube channel (www.youtube.com/channel/UCaHuyb8YzrjPnLUz7nSiauA).

Acknowledgement: The project 23FUN07 QuAHMET has received funding from the European Partnership on Metrology, co-financed from the European Union’s Horizon Europe Research and Innovation Programme and by the Participating States.