Loss channels affecting lithium niobate phononic crystal resonators at cryogenic temperature
Loss channels affecting lithium niobate phononic crystal resonators at cryogenic temperature
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DOI：
10.1063/5.0034909
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发表时间：
2020-10
影响因子：
4
通讯作者：
E. Alex Wollack;A. Cleland;Patricio Arrangoiz-Arriola;T. McKenna;R. Gruenke;Rishi N. Patel;Wentao Jiang;Christopher J. Sarabalis;A. Safavi-Naeini
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作者：
E. Alex Wollack;A. Cleland;Patricio Arrangoiz-Arriola;T. McKenna;R. Gruenke;Rishi N. Patel;Wentao Jiang;Christopher J. Sarabalis;A. Safavi-Naeini
我们研究了在超导量子电路中集成的微波频率声子晶体谐振器的性能。对于不同的设计几何形状在毫开尔文温度下，我们实现了机械内部品质因数$Q_i$以上的$10^5 - 10^6$在高微波驱动功率，对应于$5\times10^6$声子内的谐振器。通过扫描具有相同反射镜单元设计的谐振器的缺陷尺寸，我们能够经由谐振器的内部品质因子间接地观察完整声子带隙的特征。品质因数的温度依赖性的检查显示了超导和二能级系统（TLS）损耗通道如何影响器件性能。最后，我们观察到与共振TLS衰减一致的异常低温频移，并发现材料选择可以帮助减轻这些损失。
We investigate the performance of microwave-frequency phononic crystal resonators fabricated on thin-film lithium niobate for integration with superconducting quantum circuits. For different design geometries at millikelvin temperatures, we achieve mechanical internal quality factors $Q_i$ above $10^5 - 10^6$ at high microwave drive power, corresponding to $5\times10^6$ phonons inside the resonator. By sweeping the defect size of resonators with identical mirror cell designs, we are able to indirectly observe signatures of the complete phononic bandgap via the resonators' internal quality factors. Examination of quality factors' temperature dependence shows how superconducting and two-level system (TLS) loss channels impact device performance. Finally, we observe an anomalous low-temperature frequency shift consistent with resonant TLS decay and find that material choice can help to mitigate these losses.