RAITH150 Two at UNSW, Australia
Professor A. S. Dzurak’s group at the University of New South Wales, Australia and their research collaborators at the University of Twente, Netherlands and Keio University, Japan, recently reported some exciting work on SiMOS qubits (Nature Nanotechnology 9, 981-985 (2014)). It has been known that spins confined in lithographically defined GaAs quantum dots couple strongly to noise from the nuclear spin bath, which severely limits their dephasing times and control fidelities.
Prof. Dzurak and colleagues combined the best aspects of quantum dot and other silicon qubit schemes to demonstrate a gate-addressable quantum dot qubit in isotopically engineered silicon with a control fidelity of 99.6%, obtained via Clifford-based randomized benchmarking and consistent with that required for fault-tolerant quantum computing. They demonstrated a Stark shift of the electron spin resonance frequency by more than 3000 times the 2.4 kHz electron spin resonance linewidth, thus providing a direct route to large-scale arrays of addressable high-fidelity qubits that are compatible with existing manufacturing technologies.
The device structure described in the paper can be modified to use poly-silicon gate electrodes and the standard complementary metal-oxide-semiconductor (CMOS) manufacturing technologies that are currently used to fabricate more than one billion transistors on a single chip. The silicon qubit reported in the paper was fabricated using a RAITH150 Two EBL system installed at the NSW Node of the Australian National Fabrication Facility (see: http://www.anff.org.au/ ). The RAITH150 Two has been supporting a range of very high-profile research projects at that facility. Researchers interested in the above research may refer to the article links below for further reading.