Extended coherence time for spin-orbit qubit in silicon

The circular orbit of the charged electron and the spin are locked together like gears due to the very strong attraction in the spin-orbit coupling. Credit: Takashi Kobayashi

Scientists at Centre for Quantum Computation and Communication Technology (CQC2T) have demonstrated coherence times 10,000 times longer than previously recorded for spin-orbit qubits. Coherence time is the duration of time that a spin-orbit qubit in silicon can retain quantum information.

Spin-orbit qubits have been investigated for over a decade as an option to scale up the number of qubits in a quantum computer, as they are easy to manipulate and couple over long distances. However, they have always shown very limited coherence times, far too short for quantum technologies.

To increase the coherence time, the researchers first created spin-orbit qubits by introducing impurities, called acceptor dopant atoms, in a silicon crystal. The team then modified the strain in the silicon lattice structure of the chip to generate different levels of spin-orbit coupling.

The finding ultimately enables new ways of manipulating individual qubits and coupling qubits over much larger distances, which will make the chip fabrication process more flexible.

The electrical interaction also allows coupling to other quantum systems, opening up the prospects of hybrid quantum systems.

This discovery is opening up a new pathway to make silicon quantum computers more scalable and functional. (Phys.org)

The research has been published in Nature Materials.

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