Large area graphene is able to preserve electron spin over an extended period, and communicate it over greater distances than had previously been known, according to researchers based at Chalmers University of Technology. The findings, published in Nature Communications, have opened the door for the development of spintronics, with an aim to manufacturing faster and more energy-efficient memory and processors in computers.
Based on the quantum state of the electrons, spintronics is already being used in advanced hard drives for data storage and magnetic random accesses memory.
Spin as a property in electrons is very short-lived and fragile, but could make processors significantly faster and less energy consuming than they are today.
The research suggests that graphene is a promising candidate for extending the use of spintronics in the electronics industry as the thin carbon film is not only an excellent electrical conductor, but also in theory has the rare ability to maintain the electrons with the spin intact.
"In future spin-based components, it is expected that the electrons must be able to travel several tens of micrometers with their spins kept aligned. Metals, such as aluminium or copper, do not have the capacity to handle this. Graphene appears to be the only possible material at the moment," said Saroj Dash, who leads the research group at Chalmers University of Technology.
Graphene is currently produced commercially by only a few companies however, high-quality graphene can only be obtained in very small pieces. Larger pieces are often of poor quality or have other drawbacks from the perspective of the electronics industry.
Researchers at Chalmers have conducted their experiments using CVD graphene, which is produced through chemical vapour deposition. While the method gives the graphene a lot of wrinkles, roughness and other defects there are good prospects for the production of large area graphene on an industrial scale.
The CVD graphene can also be easily removed from the copper foil on which it grows and is lifted onto a silicon wafer, which is the semiconductor industry's standard material and while the material is still poor, the research group can now show parameters of spin that are up to six times higher than those previously reported for CVD graphene on a similar substrate.
"Our measurements show that the spin signal is preserved in graphene channels that are up to 16 micrometers long. The duration over which the spins stay aligned has been measured to be over a nanosecond," says Chalmers researcher Venkata Kamalakar . "This is promising because it suggests that the spin parameters can be further improved as we develop the method of manufacturing."
"We believe that these results will attract a lot of attention in the research community and put graphene on the map for applications in spintronic components," says Saroj Dash, who leads the research group at Chalmers University of Technology.
Author
Neil Tyler
Source: www.newelectronics.co.uk