Researchers have found a way to use material defects – long regarded as a hindrance in electronics – as a quantum advantage, marking a breakthrough that could enable a new generation of ultra-low-power spintronic devices.
Spintronics, or ‘spin electronics’, seeks to move beyond the constraints of conventional electronics, which depend solely on the electric charge of electrons to store and process data. By leveraging two quantum properties – spin angular momentum, which can be thought of as an electron’s intrinsic ‘up’ or ‘down’ orientation, and orbital angular momentum, describing its motion around an atomic nucleus – spintronic technologies promise faster operation, lower power consumption, and non-volatile data retention in smaller devices.
However, imperfections within materials have long presented a dilemma. While introducing defects can lower the current required to encode information, it often increases resistance, reduces spin Hall conductivity, and raises power consumption. This trade-off has been a major obstacle to developing energy-efficient spintronic systems.
A team from the Flexible Magnetic-Electronic Materials and Devices Group at the Ningbo Institute of Materials Technology and Engineering (NIMTE), part of the Chinese Academy of Sciences, reported a way to overcome this challenge. Their research, published in Nature Materials, focused on the orbital Hall effect in strontium ruthenate (SrRuO3), a transition metal oxide whose electronic behaviour can be precisely tuned. The effect arises when electrons move according to their orbital angular momentum, giving rise to distinctive transport properties.
Through precision measurements and specially designed devices, the scientists identified an unconventional scaling law that defies conventional trade-offs. Defect engineering, they found, could enhance both orbital Hall conductivity and orbital Hall angle at once – a result opposite to that observed in typical spin-based systems.
To account for the finding, the researchers proposed a Dyakonov-Perel-like orbital relaxation mechanism.
Dr ZHENG Xuan, co-first author of the paper, explained: “Scattering processes that typically degrade performance actually extend the lifetime of orbital angular momentum, thereby enhancing orbital current.”
Prof WANG Zhiming, corresponding author of the study, added: “This work essentially rewrites the rulebook for designing these devices. Instead of fighting material imperfections, we can now exploit them.”
Experimental results backed up the theoretical model, with tailored conductivity modulation achieving a threefold improvement in switching energy efficiency.
The findings provided fresh understanding of orbital transport physics and suggested a new route for designing power-efficient spintronic systems.
The research received funding from the National Key Research and Development Program of China, the National Natural Science Foundation of China, and other supporting organisations.
