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arXiv · 1706.09626

Gate-Sensing Charge Pockets in the Semiconductor Qubit Environment

X. G. Croot·S. J. Pauka·H. Lu·A. C. Gossard·J. D. Watson·G. C. Gardner·S. Fallahi·M. J. Manfra·D. J. Reilly
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Abstract

We report the use of dispersive gate sensing (DGS) as a means of probing the charge environment of heterostructure-based qubit devices. The DGS technique, which detects small shifts in the quantum capacitance associated with single-electron tunnel events, is shown to be sensitive to pockets of charge in the potential-landscape likely under, and surrounding, the surface gates that define qubits and their readout sensors. Configuring a quantum point contact (QPC) as a localized emitter, we show how these charge pockets are activated by the relaxation of electrons tunneling through a barrier. The presence of charge pockets creates uncontrolled offsets in gate-bias and their thermal activation by on-chip tunnel currents suggests further sources of charge-noise that lead to decoherence in semiconductor qubits.

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X. G. Croot, S. J. Pauka, H. Lu, A. C. Gossard, J. D. Watson, G. C. Gardner, S. Fallahi, M. J. Manfra, D. J. Reilly. 2017-06-29. Gate-Sensing Charge Pockets in the Semiconductor Qubit Environment. https://doi.org/10.1103/physrevapplied.11.064027

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