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HL: Fachverband Halbleiterphysik

HL 16: Electron spin qubits in semiconductor quantum dots (Focus session with TT)

HL 16.4: Topical Talk

Montag, 31. März 2014, 16:00–16:30, POT 051

Spin Qubits in Silicon — •Andrew Dzurak — University of New South Wales, Sydney 2052, Australia

Spin qubits in silicon are excellent candidates for scalable quantum information processing [1] due to their long coherence and the enormous investment in Si-MOS technology. Projective readout had proved challenging until single-shot measurement of a single donor electron spin was demonstrated [2] using a Si-SET and spin-to-charge conversion. The high readout fidelities > 90% and spin lifetimes T1 > 6 seconds [2] observed opened a path to electron and nuclear spin qubits in Si.

On-chip ESR of the P donor electron enables Rabi oscillations of the electron spin qubit, while Hahn echo reveals coherence T2 > 0.2 ms [3]. We also achieve single-shot readout of the 31P nuclear spin with fidelity > 99.8% and apply (local) NMR pulses to demonstrate coherent control of the nuclear spin qubit, with T2 > 60 ms [4].

Finally, I discuss recent experiments on both single-atom and Si-MOS quantum dot qubits in isotopically enriched 28Si devices, with even longer spin coherence exceeding 30 seconds.

[1] D.D. Awschalom et al., Quantum Spintronics, Science 339, 1174 (2013).

[2] A. Morello et al., Single-shot readout of an electron spin in silicon, Nature 467, 687 (2010).

[3] J.J. Pla et al., A single-atom electron spin qubit in silicon, Nature 489, 541 (2012).

[4] J.J. Pla et al., High-fidelity readout and control of a nuclear spin qubit in Si, Nature 496, 334 (2013).