Abstract
Controlling decoherence is the biggest challenge in efforts to develop quantum information hardware1,2,3. Single electron spins in gallium arsenide are a leading candidate among implementations of solid-state quantum bits, but their strong coupling to nuclear spins produces high decoherence rates4,5,6. Group IV semiconductors, on the other hand, have relatively low nuclear spin densities, making them an attractive platform for spin quantum bits. However, device fabrication remains a challenge, particularly with respect to the control of materials and interfaces7. Here, we demonstrate state preparation, pulsed gate control and charge-sensing spin readout of hole spins confined in a GeâSi coreâshell nanowire. With fast gating, we measure T1 spin relaxation times of up to 0.6Â ms in coupled quantum dots at zero magnetic field. Relaxation time increases as the magnetic field is reduced, which is consistent with a spinâorbit mechanism that is usually masked by hyperfine contributions.
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Acknowledgements
The authors thank H. Churchill, J. Medford and E. Rashba for technical help and discussions, and acknowledge support from the DARPA/QuEST programme.
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Y.H. and F.K. performed the experiments. Y.H. prepared the materials and fabricated the devices. Y.H., F.K., C.M.L. and C.M.M. analysed the data and co-wrote the paper. All authors discussed the results and commented on the manuscript.
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Hu, Y., Kuemmeth, F., Lieber, C. et al. Hole spin relaxation in GeâSi coreâshell nanowire qubits. Nature Nanotech 7, 47â50 (2012). https://doi.org/10.1038/nnano.2011.234
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DOI: https://doi.org/10.1038/nnano.2011.234