University of Cambridge > Talks.cam > Semiconductor Physics Group Seminars > Coherent spin manipulation in a CMOS transistor: an introduction to fabrication and applications of hole spin quantum bits

Coherent spin manipulation in a CMOS transistor: an introduction to fabrication and applications of hole spin quantum bits

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If you have a question about this talk, please contact Dr Joanna Waldie.

Microelectronics technology produces classical bits for logic applications based on silicon transistors that can be as small as roughly 10nm either in gate length, channel width or thickness [1]. At this scale and at low temperature such single-gate transistors behave as quantum dots in which a single spin can be isolated [2].

We will present the silicon-on-insulator CMOS nanowire technology we use to make multi-gate transistors purposely for spin Qubits, operated at low temperature, as well as for conventional yet cryogenic electronics.

Working with P-type transistors we demonstrated hole spin coherent manipulation with Rabi frequencies as high as 80MHz and an inhomogeneous dephasing time T2* currently reaching 300ns [3]. The underlying mechanism relying on g-tensor anisotropy has been studied by probing the angular dependence of the Rabi frequency [4].

At first glance for N-type spin-orbit coupling seems too weak to allow for electron spin resonance. While this is true in planar configuration, we have managed to induce electron spin resonance thanks to the nanowire geometry of our devices which enhances the spin-orbit coupling [5].

[1] S. Barraud et al., IEEE Electron Device Lett. 33, 1526 (2012)

[2] B. Voisin et al., Nano Lett. 16, 88 (2016)

[3] R. Maurand et al., Nat. Commun. 7, 13575 (2016)

[4] A. Crippa et al., https://arxiv.org/abs/1710.08690

[5] A. Corna et al., https://arxiv.org/abs/1708.02903

This talk is part of the Semiconductor Physics Group Seminars series.

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