双层石墨烯量子点中的低频电荷噪声
Low-Frequency Charge Noise in Bilayer Graphene Quantum Dots
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中文总结 AI 辅助
本研究系统表征栅极定义的双层石墨烯量子点的低频电荷噪声，确定其本征噪声水平，验证双层石墨烯可作为相干量子信息处理的可行平台。
中文摘要 AI 辅助
双层石墨烯（BLG）量子点（QDs）是极具潜力的半导体量子比特平台，但最终可能限制其相干性的低频电荷噪声仍未得到充分探究。本研究利用基于输运的噪声谱学，系统表征了栅极定义的BLG量子点中的电荷噪声，提取得到的中位振幅为$ S_\nu^{1/2}(1\rm{\text{Hz}})=1.16\rm{\text{μeV}}/\rm{\text{√Hz}} $，该值处于已确立的半导体量子点平台的报道范围内。在电荷占据、约束、源漏偏压及电荷传感器工作条件发生变化时，噪声振幅和谱依赖关系均未呈现可重复的静电调谐趋势，表明提取的是本征半导体噪声。在双量子点中也观测到一致的噪声水平，并通过独立的基于超导谐振器的色散读出得到验证。将研究扩展至包含过渡金属二硫化物层的BLG器件，发现弱邻近效应量子点中无可测量的电荷噪声增加。这些结果证实BLG是用于相干量子信息处理的可行平台。
英文摘要
Bilayer graphene (BLG) quantum dots (QDs) are a promising platform for semiconductor qubits. However, the low-frequency charge noise that may ultimately limit coherence has remained largely unexplored. Here, we systematically characterize charge noise in gate-defined BLG QDs using transport-based noise spectroscopy. We extract a median amplitude of $ S_μ^{1/2} (1~\text{Hz}) = 1.16~μ\text{eV}/\sqrt{\text{Hz}}$, placing BLG well within the range reported for established semiconductor quantum-dot platforms. Across variations in charge occupation, confinement, source-drain bias, and charge-sensor operating conditions, neither the noise amplitude nor the spectral dependence shows a reproducible trend in electrostatic tuning, indicating that we extracted the intrinsic semiconductor noise. Consistent noise levels are further observed in double QDs and confirmed using an independent superconducting resonator-based dispersive readout. Extending the study to BLG devices incorporating transition metal dichalcogenide layers reveals no measurable charge noise increase in weakly proximitized QDs. These results validate BLG as a viable platform for coherent quantum information processing.
发表机构
- ETH Zürich（苏黎世联邦理工学院）
- National Institute for Materials Science（国立材料研究所）
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