An Australian-led team of scientists have developed the key building blocks needed to make a quantum computer using silicon. Their work was published in Nature.
A research team from the University of Melbourne, the University of New South Wales, and Aalto University in Finland have been able to read out the spin orientation of a single electron on a single engineered atom in a nanoscale device they developed called “the single electron reader”.
This is key technology for "spintronics" which paves the way for a revolution in the next generation of computation and communication technology.
The team that made the breakthrough was led by Prof Andrew Dzurak and Dr Andrea Morello of School of Electrical Engineering and Telecommunications at University of NSW and Professor David Jamieson of the School of Physics University of Melbourne.
Professor David Jamieson said this discovery could unlock revolutionary applications in the silicon industry.
“Silicon continues to be of primary importance for information technology. It’s potential has not yet been fully realised, and this discovery shows is versatility.”
By using silicon—the foundation material of conventional computers, the device opens the way to constructing a simpler quantum computer, scalable and amenable to mass-production.
Professor Jamieson’s team has 20 years of experience with implanting atoms into silicon and other materials for projects involving materials modification and analysis.
His team developed a way of getting the essential dopant atoms (phosphorus in this case) into silicon in a way that was compatible with the advanced nanotechnology developed to read the electron spin in orbit around a single phosphorus atom.
The team at UNSW utilised advanced nanotechnology for making nanoscale devices led by Professor Andrew Dzurak and very sophisticated instruments for controlling and measuring the devices led by Dr Andrea Morello.
Dr Morello, who is the lead author of the paper said the device detects the spin state of a single electron on the specially engineered phosphorus atom. “The spin state of the electron controls the flow of electrons in a nearby circuit,” he said.
“Until this experiment, no-one had actually measured the spin of a single electron in silicon in a single-shot experiment.”
The overall team has built on a body of research that has put Australia at forefront of the race to construct a working quantum computer. In 1998 Bruce Kane, then at UNSW, outlined in Nature the concept for a silicon-based quantum computer, in which the qubits are defined by single phosphorus atoms in an otherwise ultra-pure silicon chip. The new device brings his vision closer.
“This breakthough is the key to unlocking the world of quantum computing and the quantum internet of the future, which has been a long time in the making,” Professor Jamieson said.
“We expect quantum computers will be able to perform certain tasks much faster than normal computers, such as searching databases, modelling complex molecules or developing new drugs,” said Professor Andrew Dzurak. “They could also crack most modern forms of encryption.”
“After a decade of work trying to build this type of single atom qubit device, this is a very special moment,” Professor Dzurak said.
Now the team has created a single electron reader, they are working to quickly develop a device for programming the electron spin orientation and create a 2-bit logic gate – the basic processing unit of a quantum computer.
The research team is part of the Australian Research Council (ARC) Centre of Excellence for Quantum Computer Technology, based at UNSW. The paper’s co-authors include Professor Robert Clark, who is now Australia’s Chief Defence Scientist and researchers from Finland’s Aalto University.
The research was funded by: The Australian Research Council Centre of Excellence Scheme, The NSW State Government, the Government of the USA, UNSW and the University of Melbourne.