Circuit-sized quantum effect observed

Magnetic quantum effects have been harnessed for the first time at the lithographic scale of semiconductors by researchers at the National Institute of Standards and Technology (NIST) and the ISIS particle accelerator (U.K.). The international team reports chaining together 100 atoms of yttrium barium nickel oxide into a quantum spin-chain that, in effect, turned the 30-nanometer long magnetic molecule into a single element. The observed quantum effect holds the promise of using these unusually large magnetic molecules as switch, memory, or computing elements in future semiconductor circuits.

"This is the first significant step toward quantum coherence on a length-scale appropriate for lithography in solid-state circuits," said Collin Broholm, a physics professor at Johns Hopkins University. "It is unusual to see quantum coherence well beyond the atomic length-scale, and that is why we are so excited by this discovery."

Quantum mechanics already enables tiny atomic-scale phenomena to be harnessed by electronics circuits, from the quantum dots in the Orion quantum computer and the quantum cascade laser, to the quantum wells of metal-insulator electronics.

However, the observation of magnetic quantum spin-chains at a scale measuring 30 nanometers could enable lithographic techniques to more easily harness such molecular-scale quantum effects in future semiconductor circuits.

"Many enormous challenges remain to be overcome to use the quantum coherence of a this spin-chain for quantum computing," said Broholm. "However, EEs should be interested, because this moves us closer to a technological application of quantum coherence. Specifically, we see quantum coherence at a length scale that is approaching the feature widths in modern IC technology."

The experiment was performed at the NIST Center for Neutron Research in the United States, and at the ISIS particle accelerator at the Rutherford Appleton Laboratory in the United Kingdom.

Broholm performed the work with colleagues at Johns Hopkins, the U.S. Department of Energy's Brookhaven National Laboratory, the University College London, Louisiana State University, Rutherford Appleton Laboratory (U.K.), the National Institute of Advanced Industrial Science and Technology (Japan) and the University of Tokyo.

The experiment was funded by the U.S. Department of Energy, the National Science Foundation, the Wolfson-Royal Society (U.K.), and by the Basic Technologies program of the U.K. Research Councils.