The spin-Hall effect helps generate 'spin currents' which enable spin information transfer without the flow of electric charge currents. Unlike other concepts that harness electrons, spin current can transfer information without causing heat from the electric charge, which is a serious problem for current semiconductor devices. Effective use of spins generated by the spin-Hall effect can also revolutionise spin-based memory applications.
The study published in Nature Materials shows how applying an electric field in a common semiconductor material can dramatically increase the efficiency of the spin-Hall effect which is key for generating and detecting spin from an electrical input.
The scientists reported a 40-times-larger effect than previously achieved in semiconductor materials, with the largest value measured comparable to a record high value of the spin-Hall effect observed in heavy metals such as Platinum. This demonstrates that future spintronics might not need to rely on expensive, rare, heavy metals for efficiency, but relatively cheap materials can be used to process spin information with low-power consumption.
As there are limited amounts of natural resources in the earth and prices of materials are progressively going up, scientists are looking for more accessible materials with which to develop future sustainable technologies, potentially based on electron spin rather than charge. Added to this, the miniaturisation approach of current semiconductor technology will see a point when the trend, predicted by Moore's law, will come to an end because transistors are as small as atoms and cannot be shrunk any further. To address this, fundamentally new concepts for electronics will be needed to produce commercially viable alternatives which meet demands for ever-growing computing power.
Co-author of the study, Dr Hidekazu Kurebayashi (UCL London Centre for Nanotechnology), said, "We borrowed 50-year-old semiconductor phenomena for our modern spintronic research. Our results are the start of the story but are a proof of principle with a promising future for spins; as we know that there is existing matured semiconductor growth technology, we can stand on the shoulders of the giants."
Original release: http://www.eurekalert.org/pub_releases/2014-08/ucl-pot080814.php