An international team of scientists has discovered a new route to ultra-low-power transistors using a graphene-based composite material.
As transistors are squeezed into ever smaller areas within computer chips, the semiconductor industry struggles to contain overheating in devices.
Now researchers from the University of York and Roma Tre University believe the solution lies in composite materials built from monolayers of graphene and the transition metal dichalcogenide (TMDC).They discovered these materials could be used to achieve a fine electrical control over the electron’s spin – its tiny compass needle.
The new research, published today in the journal Physical Review Letters, could lead the way to much needed low-energy consumption electronics.
Applications
Lead researcher Dr Aires Ferreira, of the University of York’s Department of Physics, said: “For many years, we have been searching for good conductors allowing efficient electrical control over the electron’s spin.
“We found this can be achieved with little effort when two-dimensional graphene is paired with certain semiconducting layered materials. Our calculations show that the application of small voltages across the graphene layer induces a net polarization of conduction spins.
“We believe that our predictions will attract substantial interest from the spintronics community. The flexible, atomically thin nature of the graphene-based structure is a major advantage for applications. Also, the presence of a semiconducting component opens up the possibility for integration with optical communication networks.”
Spin
The electron’s spin is like a tiny, point-like magnet which can point only in two directions, up or down. In materials where a major fraction of electrons’ spins is aligned, a magnetic response is produced, which can be used to encode information.
‘Spin currents’ – built from ‘up’ and ‘down’ spins flowing in opposite directions – carry no net charge, and therefore in theory, produce no heating. The control of spin information would therefore open the path towards ultra-energy-efficient computer chips.
The team of researchers showed that when a small current is passed through the graphene layer, the electrons’ spin polarize in plane due to ‘spin-orbital’ forces brought about by the proximity to the TMDC base. They also showed that the efficiency of charge-to-spin conversion can be quite high even at room temperature.
Properties
Manuel Offidani, a PhD student with York’s Department of Physics, carried out most of the complex calculations in this study. He said: “The current-induced polarization of the electron’s spin is an elegant relativistic phenomenon that arises at the interface between different materials.
“We chose graphene mainly because of its superb structural and electronic properties. In order to enhance the relativistic effects experienced by charge carriers in graphene, we investigated the possibility of matching it with recently discovered layered semiconductors.”
Professor Roberto Raimondi, who leads the spintronics group at Roma Tre University, said: “The possibility of orienting the electron spin with electrical currents is attracting a lot of attention in the spintronics community and arises generally as a consequence of specific symmetry conditions.
“As such this phenomenon represents a perfect example where fundamental and applied research go happily together. In this respect, our calculations demonstrate that graphene combined with the transition metal dichalcogenides is an ideal platform where abstract theoretical principles may find immediate application in showing the way to experimental and technological development.”
Efficiency
Current-induced spin polarization in non-magnetic media was first demonstrated in 2001 in semiconductors and, more recently, in metallic hetero-interfaces. Now the researchers predict that a similar effect occurs in graphene on TMDC monolayer.
Surprisingly they found that the unique character of electronic states in graphene enable charge-to-spin conversion efficiency of up to 94 per cent. This opens up the possibility of a graphene-based composite material becoming the basis for ultra-compact and greener spin-logic devices.
Dr Mirco Milletarì, a former member of the spintronics group at Roma Tre University, said: “This work follows insights gained from understanding fundamental laws that enabled us to envisage systems where the efficiency of charge-to-spin conversion can be optimal for technological applications. In particular, the much needed low-energy consumption electronics that will improve durability and performances of future devices.”
Learn more: Two-dimensional materials unlock the path to ultra-low-power transistors
The Latest on: Ultra-low-power transistors
[google_news title=”” keyword=”ultra-low-power transistors” num_posts=”10″ blurb_length=”0″ show_thumb=”left”]- sureCore announces successful tape-out of cryogenic IP demonstratoron May 8, 2024 at 12:58 am
SureCore, the ultra-low power embedded memory specialist, has announced the successful tape out of the next key part of the Innovate UK (IUK) - funded project “Development of CryoCMOS to Enable the ...
- “Magnetisation switching” can replace transistors, cutting energy demand from computing by an order of magnitudeon May 1, 2024 at 12:00 am
Globally, energy demand from computing is growing so fast the search is on to find fundamental ways to make it more efficient. “Magnetisation switching” has long been seen as a more efficient way than ...
- 2D transistors can mimic a locust's brain to avoid collision— super-efficient tech could lower the energy costs of tomorrow's AIon April 22, 2024 at 10:46 pm
Researchers have created an ultra-low power 2D transistor to mimic the collision-avoidance neurons of a locust in their autonomous robots. Scientists from the Indian Institute of Technology Bombay ...
- Researchers develop low-power artificial neurons mimicking locust brains for obstacle detectionon April 22, 2024 at 10:44 am
In a study researchers have developed ultra-low power artificial neurons capable of obstacle detection by mimicking locust brains ...
- Next Apple Watch Could Feature More Power Efficient OLED Displayon April 9, 2024 at 5:23 am
Apple plans to use new low-energy OLED panel technology in the next Apple Watch to further reduce the power consumption ... thin-film transistor (TFT) technology for its upcoming Apple Watch ...
- MIPI deployment in ultra-low-power streaming sensorson February 19, 2024 at 12:00 am
Ultra-low-power chip architects typically mitigate these sources by selecting a fabrication process with fast-switching, low-leakage transistors, lowering bias voltages, and matching clock speeds to ...
- Apple Watch Ultra 2on November 7, 2023 at 12:04 am
The Apple Watch Ultra has an always-on display technology enabled by an OLED ultra low power temperature poly ... The dual-core CPU has 5.6 billion transistors, 60 percent more than the S8 chip ...
- Transistors explained – what they are and what they doon October 24, 2022 at 11:53 am
They can amplify or switch signals with low power consumption ... hundreds of high-precision steps undertaken in ultra-clean rooms with complex and specialized machinery. Since their early days, ...
- Apple Siliconon December 31, 2020 at 10:12 pm
The M1 uses a 5nm architecture with 16 billion transistors, four high-performance ... Apple boasted the M1 as the world's fastest CPU in low-power silicon, the world's best CPU performance per ...
via Google News and Bing News