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arXiv · 1907.07549

Low-frequency charge noise in Si/SiGe quantum dots

Elliot J. Connors·JJ Nelson·Haifeng Qiao·Lisa F. Edge·John M. Nichol
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Abstract

Electron spins in silicon have long coherence times and are a promising qubit platform. However, electric field noise in semiconductors poses a challenge for most single- and multi-qubit operations in quantum-dot spin qubits. Here, we investigate the dependence of low-frequency charge noise spectra on temperature and aluminum-oxide gate dielectric thickness in Si/SiGe quantum dots with overlapping gates. We find that charge noise increases with aluminum oxide thickness. We also find strong dot-to-dot variations in the temperature dependence of the noise magnitude and spectrum. These findings suggest that each quantum dot experiences noise caused by a distinct ensemble of two-level systems, each of which has a non-uniform distribution of thermal activation energies. Taken together, our results suggest that charge noise in Si/SiGe quantum dots originates at least in part from a non-uniform distribution of two-level systems near the surface of the semiconductor.

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Elliot J. Connors, JJ Nelson, Haifeng Qiao, Lisa F. Edge, John M. Nichol. 2020-07-24. Low-frequency charge noise in Si/SiGe quantum dots. https://doi.org/10.1103/physrevb.100.165305

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